Any cancer that affects the colon and rectum is referred to as colorectal cancer, sometimes called bowel cancer, colon cancer, or rectal cancer. Constipation, diarrhea, or blood in the stool are typical symptoms of colorectal cancer. Symptoms of colorectal cancer might not appear until the disease has advanced. Screening may be beneficial for people with colorectal cancer risk factors, such as being over 50 and having a family history of the disease. Additionally, people can lower their risk of colorectal cancer by taking certain actions. This could entail adjustments to one’s diet and exercise routine.
In its early stages, colorectal cancer might not exhibit symptoms. Changes in bowel habits, such as constipation, diarrhea, narrow stools, a feeling that the bowel does not empty completely, blood in the feces that makes it appear dark brown or black, bright red blood from the rectum, abdominal pain and bloating, fatigue, and unexplained weight loss are some of the symptoms that may occur if it does. In the United States, approximately 37% of patients with colorectal cancer are diagnosed in the early stages of the disease. Colorectal cancer symptoms, however, can mimic those of numerous other illnesses. Anyone worried about these symptoms ought to consult a doctor.
Some people only become aware of symptoms when colorectal cancer spreads to other parts of their body, such as the liver or lungs. Of those who are diagnosed with colon cancer after expressing symptoms, 37% have blood in their feces or from the rectum, 34% have abdominal pain, and 23% have anemia. The affected area may influence the symptoms. For instance, jaundice, which results in yellowing of the whites of the eyes, can occur if cancer spreads to the liver. People may also appear yellowish if their skin is white or light brown. Coughing or trouble breathing may be symptoms of lung cancer.
In 2025, there will be 46,950 new cases of rectal cancer and 107,320 new cases of colon cancer in the US, according to the American Cancer Society (ACS). The third most prevalent type of cancer in the United States is colorectal cancer. S. It is the second most common cause of death among cancers that affect people of all sexes. Globally, the incidence varies. It is more prevalent in nations with stronger economies. However, the prevalence of colorectal cancer in different populations in these nations may be influenced by socioeconomic factors, such as access to cancer care and screening. Additionally, colorectal cancer rates among those under 50 have been on the rise.
Although the exact cause of colorectal cancer is unknown, a mix of environmental and genetic factors is probably to blame. Approximately 70% of cases of colon cancer () have no known cause. Three to five percent of cases may be caused by genetic mutations linked to inherited colon cancer. Although there are no inherited mutations, 20–25% of people may have a family history of the condition. Other risk factors for colorectal cancer may include: being over 50; being male; eating a lot of red or processed meats; drinking alcohol; smoking; not exercising much; being overweight or obese; having type 2 diabetes; having received radiation treatment for childhood abdominal cancer; and having polyps in the colon or rectum.
A 2023 review found that Alaskan Native and Black Americans have the highest rates of colorectal cancer deaths and incidence in the United States. S. According to the American Cancer Society, African Americans have a 40 percent higher fatality rate and a 20 percent higher chance of developing this type of cancer than white people. Inequity in employment, diet, and other aspects of daily life, as well as socioeconomic factors and disparities in screening and other healthcare aspects, could be the cause.
Tests for colorectal cancer may include stool, blood, and visual examinations, including a colonoscopy. Screening guidelines differ from one organization to the next. For instance, the United States Preventive Services Task Force advises adults between the ages of 45 and 75 to get screened for colorectal cancer. According to them, screening for adults between the ages of 75 and 85 ought to be selective and take into account personal characteristics like patient preference and general health. The American College of Physicians modified its recommendations in 2023. It suggests that starting at age 50, clinicians should screen adults with an average risk of colorectal cancer. However, it recommends that if an adult has an average risk or a life expectancy of less than ten years, clinicians should think about not screening adults between the ages of 45 and 49 who have an average risk, as well as adults over 75 who do not exhibit symptoms. Healthcare providers may advise screening to begin before the age of 45 if a person has a high risk of colorectal cancer.
Polyps can be found through screening before they develop into cancer. Additionally, it can identify colon cancer early on, when treatment is simpler. A physical examination may be the first step in diagnosing colorectal cancer. A person’s symptoms may determine the specifics of this. Other diagnostic procedures could include a colonoscopy, which gives a doctor a view of the entire colon and rectum using a long, flexible instrument with a camera. Stool tests: To look for blood, doctors may analyze a stool sample. Blood tests: To examine tumor markers, liver enzymes, and blood cells, doctors may perform blood tests. Biopsy: To check for cancerous cells in a lab, a physician may take a tissue sample during surgery or a colonoscopy. Proctoscopy: A proctoscopy involves a physician using a tiny, thin tube with a video camera attached to look inside the rectum. Imaging tests: A doctor can detect cancer or determine whether and how far it has spread with the use of imaging tests like MRIs, CT scans, and ultrasounds.
Many variables determine the optimal course of treatment for colorectal cancer. The size, location, and stage of the tumors, whether the cancer is recurrent, and the patient’s general health are some of these. Surgery is the main treatment for colorectal cancer that only affects the colon. In addition to removing tumors and impacted lymph nodes, its goals are to stop the cancer from spreading. The location of the cancer, its stage, and the intended surgical outcome may all influence the type of surgery. The following surgical techniques may be used to treat colon and rectal cancer: Polypectomy: In cases of very early-stage cancer, doctors remove the cancer during a colonoscopy as part of a polyp. Local excision: Doctors remove small, early-stage cancers along with some surrounding tissue during a colonoscopy.
A colectomy involves removing the colon and any surrounding lymph nodes, either completely or partially. Some small, early-stage rectal cancers that are near the rectum can be removed with a transanal excision. Higher rectum cancers may require transanal endoscopic microsurgery. Low anterior resection: This procedure eliminates the rectum’s lymph nodes, surrounding tissues, and cancer. Proctectomy: The entire rectum is removed during a proctectomy. The rectum, anus, and surrounding tissues are removed during an abdominal-perineal resection. People will need a colostomy bag for the rest of their lives. To manage or remove cancerous growths that obstruct the colon or rectum, people may also require surgery. If cancer spreads.
The extent of cancer’s spread is indicated by its stage. Identifying the stage aids medical professionals in selecting the best course of action. There are various staging guidelines. One set of rules states: Stage 0: Also referred to as carcinoma in situ, this is the earliest stage. Only the inner layer of the colon or rectum contains the cancer.
Stage 1: Although the cancer has penetrated the inner layer of the colon or rectum, it has not progressed past the colon or rectum’s wall.
Stage 2: Although the cancer has not yet spread to neighboring lymph nodes, it has penetrated or grown through the colon or rectum’s wall.
Stage 3: Although the cancer has not spread to other areas of the body, it has reached neighboring lymph nodes.
Stage 4: The cancer has spread to other body parts, like the lungs or liver. Sometimes the cancer is eradicated by treatment, but it returns in a different or identical location. We refer to this type of cancer as “recurrent”
Anyone can get colorectal cancer, and there is no way to avoid it. However, by going to routine screening, those with a higher-than-average risk might be able to detect it early. Additionally, people may be able to lower their risk of colorectal cancer by altering their lifestyle. Consuming a healthy, balanced diet rich in fruits, vegetables, and whole grains; maintaining or reaching a moderate weight; exercising frequently; avoiding red and processed meats; quitting or abstaining from smoking; avoiding alcohol; and taking certain vitamins and nonsteroidal anti-inflammatory drugs regularly may all help lower the risk of colorectal cancer, according to research. However, before attempting these techniques, people should consult a physician. Additionally, scientists are investigating how vaccines might be used to treat and prevent colorectal cancer.