Colorectal cancer, also known as bowel cancer, colon cancer, or rectal cancer, refers to any cancer that affects the colon and rectum. Common signs of colorectal cancer include blood in the stool, diarrhea, or constipation.
Colorectal cancer may not cause symptoms until it progresses. People with risk factors for colorectal cancer, such as being over 50 years and having a family history of colorectal cancer, may benefit from screening.
People can also take steps to reduce their risk of colorectal cancer. This may include changes in diet and exercise habits.
Colorectal cancer
- changes in bowel habits, such as:
- a feeling that the bowel does not empty fully
- blood in feces that makes it look dark brown or black
- bright red blood from the rectum
- abdominal pain and bloating
- feeling full even when a long time has passed since a meal
- fatigue
- unexplained weight loss
Around 37% of people with colorectal cancer in the United States receive a diagnosis in the early stages of the disease.
However, symptoms of colorectal cancer can be similar to those of many other health conditions. Anyone with concerns about these symptoms should seek medical advice.
Among people
- 37% have blood in feces or from the rectum
- 34% have abdominal pain
- 23% have anemia
Some people only notice symptoms in the later stages, when colorectal cancer spreads to the lungs, liver, or other areas. The symptoms can depend on the affected area.
For example, if cancer spreads to the liver, a person may have jaundice, which causes yellowing of the whites of the eyes. If a person has white or light brown skin, it may also appear yellowish.
If cancer affects the lungs, it can cause difficulty breathing or a cough.
The
Colorectal cancer is the
The incidence varies around the world. It is more common in countries with a higher economic status. However, socioeconomic factors, including access to screening and cancer care, may affect colorectal cancer rates in various populations in these countries.
Rates of colorectal cancer in people younger than 50 years have also been rising.
The cause of colorectal cancer is unclear, but it
Around
Some other colorectal cancer risk factors may
- being over the age of 50
- being male
- a diet high in red or processed meats
- consuming alcohol
- smoking
- low levels of physical activity
- overweight or obesity
- IBD
- type 2 diabetes
- having undergone radiation therapy for abdominal cancer in childhood
- polyps in the colon or rectum
Increased risk among Black Americans
According to a 2023 review, Black Americans and Alaskan Native people are more likely to develop and die from colorectal cancer than any other group of people in the U.S.
The ACS states the chance of having this type of cancer is at least
This may be due to socioeconomic factors and inequity in screening and other aspects of healthcare, as well as inequity in employment, diet, and other factors related to daily life.
Colorectal cancer screening
- stool tests
- blood tests
- visual exams, such as a colonoscopy
Screening recommendations vary depending on the organization. For example, the United States Preventive Services Task Force recommends colorectal cancer screening for adults ages 45 to 75 years.
They suggest that screening for adults ages 75 to 85 should be selective and consider individual factors such as overall health and patient preference.
In 2023, the American College of Physicians adjusted its guidance. It recommends that clinicians should offer screening for adults with an average risk of colorectal cancer from the age of 50.
However, it suggests clinicians should consider not screening adults ages 45 to 49 with an average risk and should no screen adults over 75 years without symptoms if they have an average risk or a life expectancy of less than 10 years.
If people have a high risk of colorectal cancer, healthcare professionals may suggest screening starts
Screening
Colorectal cancer diagnosis
- Colonoscopy: This procedure uses a long, flexible tool containing a camera that allows a doctor to see the whole colon and rectum.
- Stool tests: Doctors may examine a stool sample to check for blood.
- Blood tests: Doctors may use blood tests to check blood cells, liver enzymes, and tumor markers.
- Biopsy: A doctor may remove a tissue sample during a colonoscopy or surgery to test for cancerous cells in a lab.
- Proctoscopy: During a proctoscopy, a doctor looks inside the rectum with a small, thin tube that has a video camera on the end.
- Imaging tests: Imaging tests, such as MRI, CT scans, and ultrasound, may help a doctor find cancer or see if and how far it has spread.
The best approach to treatment for colorectal cancer depends on several factors. These include:
- the size and location of tumors and the cancer’s stage
- whether the cancer is recurrent
- the person’s overall health
Surgery
Surgery is the primary treatment for colorectal cancer that is limited to the colon. It aims to remove cancerous tissue, including tumors and affected lymph nodes, and prevent the cancer from spreading.
The type of surgery
- Polypectomy: For very early stage cancers, doctors remove cancer as part of a polyp during a colonoscopy.
- Local excision: During a colonoscopy, doctors remove small, early stage cancers and some surrounding tissue.
- Colectomy: A colectomy removes some or all of the colon and nearby lymph nodes.
- Transanal excision: A transanal excision can remove some small, early stage rectal cancers that are close to the rectum. Transanal endoscopic microsurgery may be necessary for cancers higher in the rectum.
- Low anterior resection: This removes the cancer, surrounding tissues, and lymph nodes around the rectum.
- Proctectomy: A proctectomy removes the entire rectum.
- Abdominoperineal resection: This surgery removes the rectum, anus, and surrounding tissues. People will require a permanent colostomy bag.
People may also need surgical procedures to remove or manage cancerous growths that block the colon or rectum. If cancer spreads to other body parts, doctors may consider surgery or other treatments.
Learn about the types of surgery for colorectal cancer.
Standard therapies
According to a 2023 review, standard therapies for colorectal cancers include:
- chemotherapy
- radiation therapy
- immunotherapy
Doctors may combine these treatments with surgery if they cannot immediately remove the cancer with surgery.
Emerging therapies
The 2023 review suggests that some emerging therapies have shown promise in treating and managing colorectal cancer in clinical and preclinical trials, including:
- targeted therapy, which uses drugs that target specific proteins in cancer cells
- probiotics
- natural therapies
- oncolytic viral therapies, which target cancer with modified viruses
People can speak with their healthcare team about emerging therapies and clinical trials to see if one may be suitable for them.
If cancer spreads and grows despite the above treatments, a doctor may suggest palliative care. This
Learn more about treatment for colorectal cancer.
The “stage” of cancer refers to how far it has spread. Determining the stage helps doctors choose the most appropriate treatment.
There are different guidelines for staging. One
- Stage 0: This is the earliest stage, also known as carcinoma in situ. The cancer is only in the inner layer of the colon or rectum.
- Stage 1: The cancer has grown through the inner layer of the colon or rectum but has not spread beyond the wall of the rectum or colon.
- Stage 2: The cancer has grown through or into the wall of the colon or rectum but has not yet reached nearby lymph nodes.
- Stage 3: The cancer has reached nearby lymph nodes but not other parts of the body.
- Stage 4: The cancer is present in other parts of the body, such as the liver or lungs.
Sometimes, treatment eliminates the cancer but it comes back in the same area or another one. This is called “recurrent” cancer.
The outlook for someone with colorectal cancer depends on various factors, including their age, their overall health, and the stage of the cancer at diagnosis.
The
The ACS gives survival rates using these stages:
- Local: The cancer has stayed in its original location.
- Regional: The cancer has spread to nearby tissues.
- Distant: It has reached more distant parts of the body.
The table below shows the estimated 5-year survival rates for a person with colon cancer from 2014 to 2020.
| Stage | 5-year survival rate |
|---|---|
| local | 91% |
| regional | 73% |
| distant | 13% |
| Overall | 63% |
The table below shows the estimated 5-year survival rates for a person with rectal cancer from 2014 to 2020:
| Stage | 5-year survival rate |
|---|---|
| local | 90% |
| regional | 74% |
| distant | 18% |
| Overall | 67% |
Colorectal cancer can affect anyone, and it is not possible to prevent it. However, people with a higher-than-average risk may be able to catch it early by attending regular screening.
People may also be able to make certain lifestyle changes to reduce their risk of colorectal cancer. This may
- eating a balanced, nutritious diet with plenty of fruits, vegetables, and whole grains
- maintaining or achieving a moderate weight
- exercising regularly
- limiting or avoiding red and processed meats
- quitting or avoiding smoking
- limiting or avoiding alcohol
Some research also suggests that certain vitamins and a regular intake of nonsteroidal anti-inflammatory drugs may reduce colorectal cancer risk. However, people should speak with a doctor before trying these methods.
Researchers are also exploring the potential of vaccines to prevent and treat colorectal cancer.
It is possible to permanently cure colon cancer and may be more likely during the earlier stages of the disease. According to the National Cancer Institute, surgery leads to a cure in 50% of people with colon cancer.
The speed of colorectal cancer progression may vary from person to person. In some cases, colorectal cancer may start to spread very early on. People can work with their healthcare team to monitor their cancer progression.
Survival rates depend on a various factors, including how far the cancer spreads. However, the ACS lists the following 5 year survival rates:
- Colon cancer: The survival rate for all stages combined is 63%.
- Rectal cancer: The survival rate for all stages combined is 67%.
Colorectal cancer is a leading cause of cancer-related death. Treatment in the early stages can remove cancerous cells and increase the likelihood of a favorable outcome.
It is important to take any signs of colorectal cancer seriously. They can also indicate other potentially severe health problems. However, symptoms of this cancer may not appear until the later stages.
Anyone with a risk of developing colorectal cancer should ask a doctor about screening. Regular screening may improve the chances of an early diagnosis.
