Overview
Colorectal cancer is cancer that develops in the colon or rectum. These organs are part of the digestive system and help remove waste from the body. Many colorectal cancers start from polyps, which are growths in the inner lining of the bowel. Finding and removing some polyps can help prevent cancer from developing.
Key Symptoms
Symptoms can include blood in or on the stool, a lasting change in bowel habits, belly pain, unexplained weight loss, tiredness, or a feeling that the bowel does not empty fully. Some people have no symptoms, especially early on. These symptoms can also happen with other conditions, but they should still be assessed by a healthcare professional.
Causes and Risk Factors
Colorectal cancer happens when cells in the colon or rectum grow out of control. Risk can be higher with older age, a personal or family history of colorectal cancer or polyps, inherited conditions such as Lynch syndrome, inflammatory bowel diseases like ulcerative colitis or Crohn's disease, smoking, alcohol use, low physical activity, excess body weight, and diets high in processed or red meat. Having a risk factor does not mean a person will definitely develop cancer.
Who Is Affected
Colorectal cancer can affect adults of any sex. It becomes more common with age, but cases in younger adults can also occur. People with a strong family history or certain inherited syndromes may develop it earlier than the general population.
Prevention
Screening is one of the most important ways to lower the chance of serious illness from colorectal cancer because it can find cancer early and may find polyps before they turn into cancer. Staying physically active, limiting alcohol, not smoking, maintaining a healthy weight, and eating a balanced diet with fiber-rich foods may also help lower risk. Screening age and test choice depend on local guidance and personal risk.
Diagnosis and Tests
Diagnosis may begin with a discussion of symptoms, family history, and a physical exam. Tests can include stool-based screening tests, colonoscopy, imaging scans, and blood tests. If an abnormal area is found, a biopsy is usually needed to confirm whether cancer is present.
Treatment Categories
Treatment depends on where the cancer is, how far it has spread, and the person's overall health. Main treatment categories include surgery, chemotherapy, radiation therapy for some rectal cancers, targeted therapy, and immunotherapy for certain tumors. Care is often planned by a team of specialists.
Living With It
Living with colorectal cancer can affect physical health, energy, digestion, work, finances, and emotional well-being. Follow-up visits are important after treatment to watch for recurrence or side effects. Support from family, community, counseling, cancer support groups, and palliative care services may help with coping and symptom burden.
When to Seek Medical Care
Make a medical appointment if you notice blood in the stool, a lasting change in bowel habits, unexplained weight loss, ongoing belly pain, unusual tiredness, or symptoms of anemia. Also seek advice if you have a family history of colorectal cancer or polyps and are unsure when to start screening. Do not ignore symptoms even if they come and go.
When It May Be an Emergency
Get urgent medical help if you have heavy rectal bleeding, black or tarry stools, severe or worsening abdominal pain, repeated vomiting, fainting, signs of bowel blockage such as a swollen abdomen with inability to pass stool or gas, or severe weakness or shortness of breath. These symptoms need prompt medical assessment.