What are the symptoms of rectal cancer? What causes rectal cancer? How is rectal cancer treated? Get a comprehensive overview with facts and expert insights.

Understanding Rectal Cancer

Rectal cancer is a type of cancer that develops in the cells of the rectum, the final section of the digestive system located between the sigmoid colon and the anus. Rectal cancer is often grouped together with colon cancer under the term “colorectal cancer.” In the United States, colorectal cancer is the third most common type of cancer and the second deadliest, making early detection and treatment crucial.

Symptoms of Rectal Cancer

In the early stages, rectal cancer may be asymptomatic. As the cancer progresses, the most common symptom is rectal bleeding. Other potential symptoms include changes in bowel habits, unexplained weakness and fatigue, diarrhea or constipation, blood or mucus in the stool, unintentional weight loss, and frequent abdominal discomfort, gas, cramps, or pain. Iron-deficiency anemia may also be a sign of rectal cancer due to blood loss.

Causes and Risk Factors of Rectal Cancer

The exact cause of rectal cancer is unknown, but it is typically caused by the uncontrolled growth and multiplication of cancerous cells that can penetrate and destroy healthy tissue. Certain inherited genetic mutations, such as those associated with hereditary nonpolyposis colorectal cancer (HNPCC) and familial adenomatous polyposis (FAP), can increase the risk of developing rectal cancer. Additionally, factors like age (diagnosis usually occurs after age 50), race (Black Americans are at higher risk), family history, radiation therapy, and conditions like inflammatory bowel disease, obesity, and type 2 diabetes may also increase the risk of rectal cancer.

Diagnosing Rectal Cancer

Rectal cancer is typically diagnosed through a combination of physical exams, screening tests, and colonoscopy. The doctor will start by taking a medical history and performing a physical exam, which may include a digital rectal exam to feel for any abnormalities. Screening tests like a fecal immunochemical test (FIT) or sigmoidoscopy may be recommended, and if these tests are positive, a colonoscopy is the next step. During a colonoscopy, the doctor can view the inside of the rectum and colon, and collect tissue samples for further examination.

Treating Rectal Cancer

The treatment for rectal cancer can vary depending on the stage and location of the cancer, as well as the individual patient’s overall health. Common treatment options include surgery, radiation therapy, and chemotherapy. In some cases, a combination of these treatments may be used. The goal of treatment is to remove the cancerous tumor, prevent the cancer from spreading, and improve the patient’s quality of life.

Prognosis and Survival Rates

The prognosis for rectal cancer can vary widely depending on the stage of the disease at the time of diagnosis. Early-stage rectal cancer has a much higher survival rate compared to advanced-stage cancer. According to the American Cancer Society, the 5-year relative survival rate for rectal cancer is 92% for localized disease, 71% for regional disease, and 16% for distant disease.

Prevention and Screening

While there is no surefire way to prevent rectal cancer, there are several steps individuals can take to reduce their risk. These include maintaining a healthy diet rich in vegetables and fiber, exercising regularly, limiting alcohol consumption, and quitting smoking. Regular screening for colorectal cancer, such as colonoscopies or other recommended tests, can also help detect the disease in its early stages when it is more treatable.

Frequently Asked Questions

What is the most common symptom of rectal cancer?
The most common symptom of rectal cancer is rectal bleeding.

What is the leading cause of rectal cancer?
The exact cause of rectal cancer is unknown, but it is typically caused by the uncontrolled growth and multiplication of cancerous cells.

How is rectal cancer usually treated?
The treatment for rectal cancer can vary but often includes a combination of surgery, radiation therapy, and chemotherapy.

What is the survival rate for rectal cancer?
The 5-year relative survival rate for rectal cancer ranges from 92% for localized disease to 16% for distant disease.

Can rectal cancer be prevented?
While there is no surefire way to prevent rectal cancer, maintaining a healthy lifestyle, regular screening, and addressing risk factors can help reduce the risk.

Is rectal cancer the same as colon cancer?
Rectal cancer and colon cancer are often grouped together under the term “colorectal cancer,” as they are both cancers of the digestive system. However, they are distinct types of cancer that can have different symptoms, treatments, and prognoses.

How quickly does rectal cancer progress?
The progression of rectal cancer can vary, but it is generally a slow-growing cancer. Symptoms may not appear until the cancer has progressed to a more advanced stage.

Causes, Symptoms, Treatment, and More

Rectal cancer is cancer that develops in cells in the rectum, which is below the sigmoid colon and above the anus.

Your rectum and colon are both part of the digestive system, so rectal and colon cancers are often grouped under the term colorectal cancer.

In the United States, colorectal cancer is the third most common type of cancer. It’s also the second deadliest, making early detection and treatment critical. Worldwide, colorectal cancer is the second most common cancer in females and the third most common cancer in males, according to a 2020 data from Worldwide Cancer Research Fund.

The American Cancer Society estimates there will be 44,850 new cases of rectal cancer in the United States in 2022. This compares with 106,180 new cases of colon cancer.

At first, rectal cancer may be asymptomatic.

As the cancer progresses, rectal bleeding is the most common symptom. Changes in your bowel habits may occur, lasting for more than a few days. You may also experience unexplained weakness and fatigue.

According to the Centers for Disease Control and Prevention (CDC), common symptoms of colorectal cancer may include:

• rectal bleeding
• changes in how often you have bowel movements
• feeling that your bowel isn’t emptying completely
• pain when you have a bowel movement
• diarrhea or constipation
• blood or mucus in your stool
• unintentional weight loss and appetite changes
• unexplained fatigue
• frequent abdominal discomfort, gas, cramps, pain

Another possible sign of rectal cancer is iron-deficiency anemia, which may occur as a result of blood loss.

While the exact cause of rectal cancer is unknown, malignant tumors develop when cancerous cells grow out of control and multiply. These cells can penetrate and destroy healthy tissue. What sets off this process isn’t always clear.

There are some inherited gene mutations that can increase your risk for rectal cancer. One of these is hereditary nonpolyposis colorectal cancer (HNPCC), also known as Lynch syndrome. This disorder significantly raises the risk of colon and other cancers. In some cases, your doctor may recommend removing your colon as a preventive measure.

Another genetic condition that may cause rectal cancer is familial adenomatous polyposis (FAP). This is a rare disorder that can cause polyps to grow in the lining of the colon and rectum.

While these polyps start off as noncancerous, they may become malignant. In fact, most people with FAP develop cancer before the age of 50. Large bowel removal may also be a preventive surgery your doctor may recommend.

Like other types of cancers, rectal cancer can spread when cancerous cells grow in healthy tissue and travel to other areas of the body.

At first, rectal cancer may affect the tissues lining the rectum. In some cases, it affects the entire rectum. The cancer may then spread to nearby lymph nodes or organs, with the liver being commonly affected. Other possible areas of metastasis can include the:

• abdomen
• brain
• lungs
• ovaries

While there’s no single known cause of rectal cancer, a number of known factors may increase your risk for developing this cancer at some point. These include the following:

• Age. Diagnosis usually occurs after age 50, although rates are increasing among younger people.
• Race. Black Americans are at higher risk than other groups of developing rectal cancer. One reason for this may be inequities in healthcare access.
• Family history. Personal or family history of colorectal cancer can raise risk.
• Genetics. Lynch syndrome or FAP are two genetic conditions that may increase your risk.
• Radiation therapy. Previous radiation treatment to the abdomen can increase risk.

Other conditions that may increase risk include:

• ovarian cancer
• polyps
• inflammatory bowel disease, especially if you’ve lived with it for 8 years or longer
• obesity
• type 2 diabetes that’s not well managed

Some lifestyle factors that may play a role in colorectal cancer are:

• eating a diet low in vegetables and fiber
• eatinga diet high in red and processed meat
• a lack of exercise
• smoking
• consuming three or more alcoholic drinks per day

Rectal cancer is diagnosed with a combination of the following:

Physical exam and screening tests

The doctor will likely begin by taking your medical history and performing a physical exam. This may include inserting a gloved finger into your rectum to feel for lumps.

The doctor might next recommend a fecal immunochemical test (FIT) or a sigmoidoscopy. The screening schedule for these tests will vary depending on your risk level. If these tests are positive for cancer, a colonoscopy is the next step.

Colonoscopy

In a colonoscopy, a doctor uses a thin tube with a light and camera at the end to view the inside of your rectum and colon. They can usually remove any polyps they find at this time.

During the colonoscopy, the doctor can also collect tissue samples for later examination in a lab. These samples can be viewed under a microscope to determine if they’re cancerous. They can also be tested for genetic mutations associated with colorectal cancer.

Blood tests

The doctor may also order a blood test. A high level of carcinoembryonic antigen (CEA), a substance made by cancerous tumors, in your bloodstream may indicate rectal cancer.

Imaging tests

Once the doctor makes their diagnosis of rectal cancer, their next step is to determine how far it might have spread.

The doctor may use an endorectal ultrasound to examine your rectum and surrounding area. For this test, a doctor inserts a probe into your rectum to produce a sonogram, a type of image.

The doctor may use other imaging tests to look for signs of cancer throughout your body. These include:

• CT or PET scan, which may help the doctor see the extent of cancer in the rectum, colon, and other organs
• MRI, which can help the doctor determine the stage of the cancer

No matter where it starts, cancer can spread, or metastasize, through tissue, the lymphatic system, or the bloodstream to reach other parts of the body.

Staging cancer indicates how far the cancer has progressed, which can help doctors decide the best treatment.

Below are the stages of rectal cancer.

Stage 0 (carcinoma in situ)

Only the innermost layer of the rectum wall contains abnormal cells.

Stage 1

Cancer cells have spread past the innermost layer of the rectum wall but not to lymph nodes.

Stage 2

Cancer cells have spread into or through the outer muscle layer of the rectum wall but not to lymph nodes. This is often referred to as stage 2A. In stage 2B, the cancer has spread into the abdominal lining.

Stage 3

Cancer cells have spread through the outermost muscle layer of the rectum and to one or more lymph nodes. Stage 3 is often broken up into substages 3A, 3B, and 3C based on the amount of lymph node tissue affected.

Stage 4

Cancer cells have spread to distant sites, like the liver or lungs.

In recommending treatment, the doctor and care team will consider:

• tumor size
• where cancer may have spread
• your age
• your general health

This can help them determine the best combination of treatments, as well as the timing of each treatment.

Below are the general guidelines for treatment by stage. This list contains potential treatment options. Not all patients may require the treatment options listed for each stage.

Stage 0

• removal of suspicious tissue during colonoscopy
• removal of tissue during a separate surgery
• removal of tissue and part of the surrounding area

Stage 1

• local excision or resection
• radiation therapy for some patients
• chemotherapy for some patients

Stages 2 and 3

• surgery
• radiation therapy
• chemotherapy

Stage 4

• surgery, possibly in more than one area of the body
• radiation therapy
• chemotherapy
• targeted therapies, such as monoclonal antibodies or angiogenesis inhibitors
• cryosurgery, a procedure that uses a cold liquid or a cryoprobe to destroy abnormal tissue
• radiofrequency ablation, a procedure in which radio waves are used to destroy abnormal cells
• a stent to keep the rectum open if it’s blocked by a tumor
• palliative therapy to improve overall quality of life

You can also ask your doctor about clinical trials that might be a good fit. Many current therapies for cancer began as clinical trials. These trials may try different combinations of current treatment, treatments that have been approved by the U.S. Food and Drug Administration (FDA) for other conditions, or new treatments.

In some cases, therapy as part of a clinical trial may be covered by insurance or covered by a sponsor of the trial.

Clinical trials can help advance scientists’ understanding of cancer and investigate new treatment options. Participating may offer additional options for your treatment. You can learn more about clinical trials for rectal cancer at the National Cancer Institute.

Rectal cancer may spread outside of the rectum, eventually affecting surrounding tissues, lymph nodes, and organs.

You may also be at risk of developing second cancers, which occur after treatment of the initial cancer. Rectal cancer may especially increase the risk of secondary cancers affecting the:

• anus
• colon
• kidneys
• lungs
• small intestine
• vagina

A diagnosis of colorectal cancer in the early stages, before it spreads, can improve your chances of survival.

According to the CDC and the American Cancer Society, the best way to reduce your overall risk for developing colorectal cancer is to begin regular screenings beginning at age 45. Depending on family history, genetics, and other risk factors, your doctor may recommend screenings sooner than this.

Colon and rectal cancer can be diagnosed early when discovered through routine screenings, such as a routine colonoscopy or stool test. Highly sensitive stool tests can detect the presence of cancer. If abnormal cells are discovered, a timely colonoscopy should also be performed.

You may also be able to help prevent rectal cancer by adopting a healthy lifestyle and eliminating related risk factors such as inactivity, smoking, and eating red or processed meats.

Advances in treatment over the last few decades have improved the overall outlook for people with rectal cancer. In fact, many cases of rectal cancer can be treated successfully.

It’s also important to consider the 5-year survival rate, which is determined based on the average number of people who are alive after 5 years or being diagnosed with a certain type of cancer and its stage. The overall 5-year survival rate for rectal cancer is 67 percent for all stages combined.

The 5-year relative survival rate by stage is:

• Localized: 89 percent
• Regional: 72 percent
• Distant: 16 percent

It’s important to note that these figures are based on information between 2010 and 2016. Since then, treatments may have been modified and improved. These numbers may not reflect current survival rates.

For people with rectal cancer, your outlook can depend on other factors that can include:

• where cancer may have spread
• whether your bowel is blocked
• if the entire tumor can be surgically removed
• age and general health
• whether this is a recurrence
• how well you tolerate treatment

When it comes to your individual outlook, the best source of information is your own doctor.

Rectal cancer, commonly referred to as colorectal cancer, is common in both the United States and worldwide. The symptoms of rectal cancer may not appear until the later stages, which makes early, regular screenings an important factor in both detection and treatment.

Treatment and screening options may continue to evolve, but it’s also important to reduce your own risk if you can. Talk with your doctor about any personal concerns you have about rectal cancer risks, and whether you’re experiencing any unusual bowel-related symptoms.

Rectal cancer | Macmillan Cancer Support

Clinical Oncologist Katherine Aitkens explains bowel cancer (which includes rectal cancer), giving an overview of bowel cancer symptoms, diagnosis and treatment.

The rectum is part of the large bowel, which is part of the digestive system. Rectal cancer is more common in older people. In the UK, almost 6 in 10 bowel cancer cases (58%) each year are diagnosed in people aged 70 and over.

We have more information about other types of bowel cancer including:

• colon cancer
• anal cancer
• small bowel cancer
• anorectal melanoma.

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Booklets and resources

Understanding rectal cancer

This booklet is about rectal cancer. It is for anyone who has been diagnosed with rectal cancer. There is also…

Understanding rectal cancer

The audiobook explains what rectal cancer is, and how it is diagnosed and treated. It also talks about your…

Some people may start by seeing their GP because they have symptoms. Symptoms of rectal cancer can include:

• blood in your poo (stools)
• bleeding from the back passage
• a change in your normal bowel habit.

If you are worried about rectal cancer, we have more information about bowel cancer symptoms.

Other people may be diagnosed by:

• Bowel screening is a way of finding bowel cancer at an early stage before it causes symptoms.

• This is when part of the bowel becomes blocked. It may cause symptoms such as tummy pain, nausea and vomiting, and constipation.

If you have any symptoms or notice anything that is unusual for you, you should see your GP straight away.

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  Do I have cancer?
  

The exact cause of colorectal cancer (colon or rectal cancer) is unknown. But, things called risk factors can increase the chance of a person developing it. Having one or more risk factors does not mean you will definitely get rectal cancer. And if you do not have any risk factors, it does not mean you will not get rectal cancer.

If you have symptoms, you will usually begin by seeing your GP, who will examine you. If they think that your symptoms could be caused by cancer, they will refer you to a specialist doctor.

At the hospital

The doctor will ask you about your general health and any previous medical problems you have had. They will also ask whether you have a family history of bowel cancer.

The doctor will examine you and you will usually also have one of the following tests:

• A rectal examination is when the doctor places a gloved finger into your back passage to feel for any lumps or swelling.

• You usually have a blood test to check your level of red blood cells. If you have a low number of red blood cells, this is called anaemia. You will also have blood tests to check if your liver and kidneys are working normally.

You may also have some of the following tests:

• A colonoscopy looks at the inside of the whole length of the large bowel. You can usually have this test as an outpatient. It takes about an hour.

• In a virtual colonoscopy, a computerised tomography (CT) scanner takes a series of x-rays. This builds up a three-dimensional picture of your bowel.

• A sigmoidoscopy looks at the inside of the rectum and the part of the colon closest to the rectum (the sigmoid colon). You can usually have it as an outpatient.

Waiting for tests can be a difficult time, we have more information that can help.

Further tests for rectal cancer

If any of your biopsies show that there is cancer in the rectum, you will have more tests. The results will help you and your doctor decide on the best treatment for you. Some tests may be repeated during and after treatment. You may have any of the following tests:

• Your blood may be tested for a protein called carcinoembryonic antigen (CEA). Some people with bowel cancer have higher levels of this protein.

• A CT (computerised tomography) scan uses x-rays to build a three-dimensional (3D) picture of the inside of the body.

• An MRI scan uses magnetism to build up a detailed picture of areas of your body.

• An endorectal ultrasound scan (ERUS) can show the size and location of a cancer in the rectum, using sound waves to build up a picture. This test may be used to help plan your operation.

• A PET-CT scan is a combination of a CT scan, which takes a series of x-rays to build up a three-dimensional picture, and a positron emission tomography (PET) scan. A PET scan uses low-dose radiation to measure the activity of cells in different parts of the body.

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The results of your tests help your doctors find out more about the size and position of the cancer and whether it has spread. This is called staging.

A doctor decides the grade of the cancer by how the cancer cells look under the microscope. This gives an idea of how quickly the cancer might grow or spread.

Knowing the stage and grade helps your doctors plan the best treatment for you.

A team of specialists will meet to discuss the best possible treatment for you. This is called a multidisciplinary team (MDT).

Your doctor will explain the different treatments and their side effects. They will also talk to you about the things you should consider when making treatment decisions.

Surgery is the most common treatment for colon cancer. But the treatment you have depends on the stage of the cancer and where it is in the rectum. It also depends on your general health and preferences. Find out more about treatment options for rectal cancer.

Treatment may include:

• Surgery is often used to remove cancer or areas affected by the cancer. It may also be used to help control symptoms

• Chemotherapy uses anti-cancer drugs to destroy cancer cells. You may have it before or after surgery. It may be given as as the main treatment if the cancer has spread.

• Radiotherapy is the use of high-energy rays, usually x-rays and similar rays (such as electrons) to treat cancer. It is sometimes given before surgery to shrink the cancer or it may be used to control symptoms.

• Chemoradiation is a combination of chemotherapy and radiotherapy. It is also sometimes called chemoradiotherapy.

• Targeted therapy drugs target something in or around a cancer cell that is helping it grow and survive. Targeted therapies are sometimes used to treat bowel cancers (colon or rectal) that have spread to other parts of the body.

You may also have some treatments as part of a clinical trial.

Most people have changes in how their bowel works after treatment for rectal cancer. These effects usually improve over time. We have more information about managing bowel changes caused by treatment.

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Follow-up

The aim of follow-up care is to make sure everything is going well and to find out if you have any concerns. The appointments are usually every few months in the first year.

We have more information on follow-up care after treatment.

You may get anxious between appointments. This is natural. It may help to get support from family, friends or a support organisation. 

Macmillan is also here to support you. If you would like to talk, you can: 

• Call the Macmillan Support Line on 0808 808 00 00.
• Chat to our specialists online.
• Visit our bowel cancer forum to talk with people who have been affected by rectal cancer, share your experience, and ask an expert your questions.

Sex life

Rectal cancer and its treatment can affect your sex life. Changes may get better over time, but sometimes they are permanent. If you have any problems or are worried about this talk to your doctor or nurse. They can explain what to expect and there are often things that can help.

Fertility

Some cancer treatments can affect whether you can get pregnant or make someone pregnant. If you are worried about this, it is important to talk with your doctor before you start treatment.

Well-being and recovery

Even if you already have a healthy lifestyle, you may choose to make some positive lifestyle changes after treatment. Making small changes such as eating well and keeping active can improve your health and well-being and help your body recover.

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Find accessible cancer information in a format that works for you.

• Below is a sample of the sources used in our rectal cancer information. If you would like more information about the sources we use, please contact us at [email protected]

  R Glynne-Jones, PJ Nilson, C Aschele et al. ESMO-ESSO-ESTRO Clinical practice guidelines for diagnosis, treatment and follow up for anal cancer. July 2014. European Society of Medical Oncology. Available from www.esmo.org/Guidelines/Gastrointestinal-Cancers/Anal-Cancer (accessed October 2019).

  National Institute for Health and Excellence (NICE). Colorectal cancer: diagnosis and management clinical guidelines. Updated December 2014. Available from www.nice.org.uk/guidance/cg131 (accessed October 2019).

  Association of Coloproctology of Great Britain & Ireland (ACPGBI). Volume 19. Issue S1. Guidelines for the management of cancer of the colon, rectum and anus. 2017. Available from www.onlinelibrary.wiley.com/toc/14631318/19/S1 (accessed October 2019).

  National Institute for Health and Care Excellence. Preoperative high dose rate brachytherapy for rectal cancer. 2015. Available from www.nice.org.uk/guidance/ipg531 (accessed October 2019).

  BMJ. Best practice colorectal cancer. Updated 2018. Available from www.bestpractice.bmj.com/topics/en-gb/258 (accessed October 2019).

• This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer. It has been approved by Chief Medical Editor, Professor Tim Iveson, Consultant Medical Oncologist.

  Our cancer information has been awarded the PIF TICK. Created by the Patient Information Forum, this quality mark shows we meet PIF’s 10 criteria for trustworthy health information.

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Colorectal cancer – prevalence, symptoms, screening and diagnosis

Anvar Yuldashev tells –

What is colorectal cancer

“Colorectal cancer” is a collective term for cancer (tumor) of various parts of the colon (colon) and rectum (rectum). Among many oncological diseases, this pathology remains the least covered and most covered with myths and fears of patients, but, nevertheless, modern possibilities for early diagnosis give reason to consider CRC at ~ 95% preventable cancer.

The prevalence of colorectal cancer

The statistics of the developed countries of the world show a steady increase in newly diagnosed cases of colon and rectal cancer compared with malignant tumors of any other localization, except for lung cancer. In the world as a whole, the incidence is not the same: the highest incidence rates are in Australia and New Zealand, Europe and North America, and the lowest in Africa and Central and South Asia. Such geographic differences seem to be determined by the degree of influence of risk factors for CRC – diet, bad habits, environmental factors against the background of a genetically determined susceptibility to the development of this type of cancer.

In Russia, colorectal cancer occupies one of the leading positions. Among men who fell ill with malignant neoplasms, CRC is in 3rd place after lung and stomach cancer, and in women, respectively, after breast cancer and skin cancer. An alarming fact is the high level of mortality in the 1st year of life after diagnosis, due to the fact that more than 70% of patients with colon cancer and more than 60% of patients already have advanced forms of cancer (Stage III-IV) when they first visit a doctor. with rectal cancer, with about 40% of patients undergoing surgical treatment.

Approximately 140,000 new cases and approximately 50,000 deaths from CRC are reported in the United States each year. Surprisingly, it is in the United States that there is a slow but steady downward trend in the incidence of CRC, and survival rates for CRC are among the highest in the world. Reporting data from the US National Cancer Institute show that 61% of patients with this diagnosis have overcome the five-year survival rate.

In the US and many other Western countries, improved outcomes have been achieved, in particular, by the timely detection and removal of colonic polyps, early detection of CRC, and more effective treatment. Unfortunately, in many countries with limited resources and a different health infrastructure, especially in Central and South America and Eastern Europe, the death rate from CRC continues to rise.

Risk factors for colorectal cancer

Colorectal cancer most often develops as degeneration of adenomatous (glandular) polyps.

Although hereditary predisposition significantly increases the risk of developing CRC, most cases are sporadic (in other words, unpredictable, episodic) and not familial: approximately 80-95% of cases are sporadic versus 5-20% with a hereditary cause. But among all other human cancers, CRC shows the greatest association with familial incidence. Studies of the molecular mechanisms of colorectal cancer development have identified a number of genetic disorders, most of which are inherited in an autosomal dominant manner and significantly increase the risk of developing cancer. Familial adenomatous polyposis and Lynch syndrome (hereditary non-polyposis colorectal cancer) are the most common familial cancers with known genetic defects, together accounting for only about 5% of colorectal cancers.

Other well-known predisposing factors include inflammatory bowel disease (ulcerative colitis, Crohn’s disease) – the risk of cancer increases with the duration of these diseases. The overall incidence of colorectal cancer begins to increase approximately 8-10 years after the onset of inflammatory bowel disease and rises to 15-20% after 30 years. The main risk factors are the duration of the disease, the prevalence of the lesion, young age and the presence of complications.

Age is a significant risk factor: colorectal cancer is uncommon before age 40, but the frequency of colorectal cancer increases in each subsequent decade and reaches a maximum at 60-75 years.

There are factors that increase the risk of colorectal cancer. It has been established that populations of people in which the incidence of colorectal cancer is high eat food that is poor in fiber, but at the same time high in animal protein, fat and refined carbohydrates. Obesity increases the risk of developing colorectal cancer by about 1.5 times, and more so in men. Excessive alcohol consumption and smoking are also among the factors that increase the sporadic incidence of colon polyposis and colorectal cancer, and significantly increase the risk of cancer in patients with hereditary colon diseases (eg, Lynch syndrome).

What is colorectal cancer screening?

These are methods to actively identify individuals with risk factors for CRC or asymptomatic CRC, based on the use of special diagnostic methods. Screening for colorectal cancer can significantly reduce the chances of developing it by detecting precancerous bowel disease or cancer at an early stage and providing timely treatment.

Screening is primarily for individuals with first-line relatives (children, parents, siblings) who have cases of colon or rectal cancer, adenomas, and inflammatory bowel disease. The presence of such a diagnosis in a relative increases the risk by about 2 times compared with the general population.

Recommendations from several colorectal cancer communities (American College of Gastroenterology, Multisociety Task Force on Colorectal Cancer from the American Cancer Society, American College of Radiology) provide guidance on the timing of the first colonoscopy for the following patients:

• early, up to 40 years, in patients with close relatives with intestinal adenoma diagnosed before the age of 60;

• 10-15 years earlier than the “youngest” CRC in the family was diagnosed and/or this diagnosis was made at 60 years of age or younger.

The timing of screening tests may be changed if the patient has additional risk factors for CRC: radiation exposure of the abdomen at an early age for cancer, a diagnosis of acromegaly (which may develop adenomatosis of the colon), a previous kidney transplant (as a reason for long-term immunosuppressive therapy) .

Symptoms of colorectal cancer

Tumors of the colon and rectum grow slowly and take a long time before the first signs can appear. Symptoms depend on the location of the tumor, the type, extent of spread, and complications. A feature of colorectal cancer is that it “makes itself known” quite late. In other words, such a tumor is not visible and imperceptible to the patient; only when it grows to a significant size and grows into neighboring organs and / or gives metastases, the patient begins to feel discomfort, pain, note blood and mucus in the stool.

The right part of the large intestine has a large diameter, a thin wall and its contents are liquid, so blockage of the intestinal lumen (obturation) develops last. More often, patients are concerned about gastrointestinal discomfort due to disorders of the functions of neighboring organs – the stomach, gallbladder, liver, pancreas. Bleeding from the tumor is usually occult, and fatigue and morning sickness due to anemia may be the only complaints. Tumors sometimes become large enough to be felt through the abdominal wall before other signs appear.

The left part of the colon has a smaller lumen, the feces in it are semi-solid, and the tumor tends to narrow the lumen in a circle, causing intestinal obstruction. Stagnation of intestinal contents activates the processes of decay and fermentation, which is accompanied by bloating, rumbling in the abdomen. Constipation gives way to copious, loose, offensive stools. The patient is concerned about colicky pains in the abdomen. The stool can be mixed with blood: bleeding in colon cancer is most often associated with the disintegration or ulceration of the tumor. Some patients have symptoms of bowel perforation with the development of peritonitis.

In rectal cancer, the main symptom is bleeding during defecation. Whenever bleeding or bleeding from the anus is observed, even in the presence of severe hemorrhoids or diverticular disease, concomitant cancer should be ruled out. There may be an urge to defecate and a feeling of incomplete emptying of the bowels. The pain appears when the tissues surrounding the rectum are involved.

In some cases, even before the onset of intestinal symptoms, patients may show signs of metastatic disease – the spread of the tumor to other organs, for example, an enlarged liver, ascites (accumulation of fluid in the abdominal cavity), and an increase in supraclavicular lymph nodes.

Violation of the general condition of patients can be observed in the early stages and is manifested by signs of anemia without visible bleeding, general malaise, weakness, and sometimes fever. These symptoms are characteristic of many diseases, but their appearance should be the reason for an immediate visit to a general practitioner.

There are many “masks” for colorectal cancer, so you should consult a doctor:

• with increased fatigue, shortness of breath, pallor uncharacteristic for the patient, if they were not there before;

• for prolonged constipation or diarrhoea;

• for frequent/persistent abdominal pain;

• if there is visible blood in the stool after a bowel movement;

• in the presence of occult blood in the analysis of feces.

In case of acute pain in the abdomen, with bloating or asymmetry of the abdomen, in the absence of stool and gas, you should call an ambulance or urgently seek medical help.

Screening and diagnosis of CRC

In the presence of the complaints described above, as well as in patients belonging to a high risk group for CRC, an examination is carried out. The most informative and generally accepted method of early diagnosis is colonoscopy – an endoscopic (intraluminal) examination of the mucous membrane of the rectum, large intestine and part of the small intestine (for about 2 m). All pathologically altered tissues and polyps will either be completely removed during colonoscopy, or pieces will be taken from them and sent for histological examination. If the mass is sessile or cannot be safely removed with a colonoscopy, the doctor will consider surgery.

Once cancer is diagnosed, patients should have a CT scan of the abdomen and chest to check for metastatic lesions, as well as laboratory tests to assess the severity of anemia.

In 70% of patients with colorectal cancer, there is an increase in the level of serum cancer-embryonic antigen (CEA) and tumor marker CA19.9. In the future, monitoring of CEA and CA19.9 may be useful for early diagnosis of tumor recurrence. Other markers of colorectal cancer are also studied according to indications.

Colonoscopy is the primary screening test for patients over 50 years of age at moderate risk. In the presence of polyps or other pathology in the colon and rectum, the regularity of studies can increase to annual or every 3-10 years. Assessing the degree of risk of developing colorectal cancer in patients with bowel diseases, the doctor decides on the frequency of examinations individually for each patient.

Only such an active position of doctors regarding the early diagnosis of polyps and the prevention of tumors of the colon and rectum has led to a slowdown in the growth rate of colorectal cancer in the United States.

Treatment of colorectal cancer

Surgery for colorectal cancer can be performed in 70-95% of patients without evidence of metastatic disease. Surgical treatment consists in removing a segment of the intestine with a tumor with a local lymphatic apparatus, followed by connecting the ends of the intestine (creating an anastomosis) to preserve the natural ability to empty the intestine. In case of rectal cancer, the volume of the operation depends on how far from the anus the tumor is located. If it is necessary to completely remove the rectum, a permanent colostomy is formed (a surgically created opening in the anterior abdominal wall to remove the intestine), through which the contents of the intestine will be emptied into the pouch. Given the modern advances in medicine and devices for the care of a colostomy, the negative consequences of this operation are minimized.

If liver metastases are present in non-malnourished patients, removal of a limited number of metastases is recommended as a further surgical option. This operation is performed if the primary tumor has been completely removed, the liver metastasis is in one lobe of the liver, and there are no extrahepatic metastases. Survival after surgery for 5 years is 6-25%.

IMPORTANT!!!

The effectiveness of colorectal cancer treatment depends on the stage of the disease at which the patient consulted a doctor. Only early diagnosis of colorectal cancer makes it possible to make the most of the entire range of modern treatment methods and achieve satisfactory results.

Attentive attitude to your body and timely seeking qualified medical assistance increases the chances of continuing an active life even with such a serious oncological disease.

Colorectal cancer: symptoms, diagnosis – laboratory article DNAOM

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37383

Published:
06/19/2019

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Updated:

07/07/2022

• Oncology

What is colorectal cancer?

Colon and rectal cancer is cancer that starts in the colon or rectum. Colon and rectal cancers are often grouped together because they share many common features. Colorectal cancer is a tumor that originates from the epithelial cells of the large intestine.

Colorectal cancer ranks third among malignant neoplasms after lung and skin cancer in Russia.

How does colorectal cancer start?

Polyps in the colon or rectum.

Most cases of colorectal cancer are associated with the formation of polyps, outgrowths of the mucous membrane of the colon or rectum. Some types of polyps can transform into malignant tumors over time, but not all. The process of malignancy depends on the type, size, localization and type of polyp.

There are 3 main types of polyps:

1) Adenomatous polyps or adenomas. In 9% of cases, they turn into cancer, so their formation is identical to precancerous conditions.

2) Villous polyps. The probability of malignancy is 50%.

3) Hyperplastic polyps and inflammatory polyps. These polyps are more common, but in general, are not precancerous.

Factors that increase the risk of colorectal cancer

• Detection of a polyp larger than 1 cm.

• Detection of more than 2 polyps.

• Dysplastic processes in the mucous membrane of the colon at the site of removal of the polyp. Dysplasia implies the presence of cells with atypia. The cells are not cancerous, but are able to transform into them with the development of carcinoma in situ and invasive cancer.

Other risk factors for disease:

• Features of nutrition. The prevalence of animal fats and protein, easily digestible carbohydrates and a low proportion of fiber in the diet are a risk factor for colorectal cancer. It is believed that the above food components change the metabolism and composition of bile acids, as well as the qualitative and quantitative composition of the intestinal microflora, thereby increasing the risk of disease.

• Obesity and overweight.

• Alcohol.

• Age. The likelihood of colorectal cancer increases with age and peaks in the age group of 70 years and older.

• Low physical activity.

• Genetic factors. Some congenital diseases, such as adenomatous polyposis, Gardner’s syndrome, Turcot’s syndrome, hereditary non-polyposis colon cancer, increase the likelihood of developing colorectal cancer in the future.

Colorectal cancer risk groups

Those at high risk for colorectal cancer include those with ulcerative colitis, Crohn’s disease, celiac disease, and other chronic inflammatory bowel diseases. Additionally, at risk are people cured of cancer of the colon, ovary, uterine body and mammary glands and treated for intestinal polyposis. Patients with close relatives suffering from colon and rectal cancer deserve special attention.

Cancer classification

Most often, a cancerous tumor is localized in those departments where intestinal contents are retained – in the sigmoid and caecum.

Depending on the type of tumor, there are exophytic and endophytic (infiltrative) forms of the tumor. Exophytic tumors grow into the lumen of the large intestine in the form of a polyp or nodule. Infiltrative tumors affect the entire thickness of the intestinal wall, covering it along the entire perimeter and narrowing the lumen.

Malignant cells of tumor tissue can penetrate into local blood or lymphatic vessels, spread to regional lymph nodes and further to the rest of the body.

The stage of colorectal cancer depends on how deeply the tumor has affected the organ and spread beyond it.

Familial cases

The risk of developing colorectal cancer is higher in people with a family history of the disease. Cancer in first-degree relatives such as parents and siblings is a big concern, but cancer in distant relatives is also important. The presence of two or more relatives with colorectal cancer in the family is more significant than the presence of only one relative. The age at which the cancer was diagnosed must also be taken into account: if the cancer was discovered at a younger age, for example, before 60 years of age, then screening activities should begin 10–15 years before this age.

Individuals with a family history of the disease are advised to undergo genetic counseling. A geneticist, based on a family history, can calculate individual risks of developing the disease and recommend, if necessary, genetic testing. Based on genetic testing, preventive measures can be suggested to help reduce the risk of colorectal cancer. For example, participating in screening more than once a year, changing diet, etc.

Clinical manifestations and symptoms of the disease

The most common symptoms are pain, impaired motor-evacuation function (discomfort, feeling of heaviness, vomiting, loss of appetite), the presence of pathological discharge with feces. In most cases, the tumor remains unrecognized for a long time, and only if it goes beyond the organ or reaches a large size, a person can complain and consult a doctor.

When the colon is affected, it matters which section is affected. There is a difference in the cancer clinics of the right and left colon.

With right-sided localization of the tumor, the pain syndrome is observed 2-3 times more often than with the left-sided one. Tumor growth is accompanied by paroxysmal pain, predominantly on the right, intestinal disorders, fever, fatigue and weakness. Quite often, patients note gastrointestinal discomfort, indicating functional disorders of neighboring sections of the gastrointestinal tract.

Left-sided lesion of the colon is more often associated with the clinic of intestinal obstruction, therefore, the presence of the disease may indicate the alternation of constipation and liquid fetid stools, bloating. The pain is colicky in nature.

Colon cancer is accompanied by bleeding during bowel movements. A frequent symptom is “intestinal discomfort” – a feeling of incomplete emptying and the presence of a foreign body in the rectum, as well as constipation, which occurs in 40% of cases.

In the presence of metastases, ascites, an increase in the size of the liver and lymph nodes are observed.

Colorectal cancer diagnostics

Diagnosis of colorectal cancer is complex and includes examination, endoscopic, morphological, and ultrasound methods.

The first diagnostic method is an external examination, which is carried out using digital rectal examination (DRE) of the anus and rectum. Up to 70% of tumors can be diagnosed using PRI. If there are indications, examination and palpation of the inguinal lymph nodes, palpation of the abdomen and liver are performed.

Sigmoidoscopy – allows you to examine the rectum and distal sigmoid colon (for 30 cm). During the procedure, it is possible to take a piece of material for a biopsy.

Irrigoscopy – X-ray examination of the colon. With the help of barium enema with double contrasting, the doctor determines the extent of the tumor, determines the form of growth, the presence of fistulas and ulcerations. It is carried out in various projections, reveals formations up to 0.5 cm in diameter.

Colonoscopy – endoscopic examination of the rectum, colon, part of the small intestine (over 2 m). The colonoscopy method is convenient in that it allows you to examine the entire mucosa and take a tissue biopsy for histological examination in suspicious cases.

Ultrasound method – allows you to assess the prevalence of the tumor process.