What is Colorectal Cancer?
Colorectal cancer is a type of cancer that begins in the colon or rectum. Depending on where they start, these cancers can also be named colon cancer or rectal cancer. Colorectal cancer is often grouped together because they share many features.
What Causes Colorectal Cancer?
The exact cause of colorectal cancer is not known. However, most colorectal cancers begin as a
polyp—a growth on the inner lining of the colon or rectum. Some polyps can change into cancer over time (usually many years), but not all polyps become cancer. The chance of a polyp turning into cancer depends on the type of polyp it is.
Age: Most colorectal cancers are found in people aged 50 and older.
Family History: Having a history of colorectal cancer or polyps in close relatives.
Inherited Syndromes: Certain genetic syndromes such as
Lynch syndrome or
Familial adenomatous polyposis (FAP).
Lifestyle Factors: Diet high in red or processed meats, smoking, heavy alcohol use, and being overweight.
Health Conditions: Long-standing inflammatory diseases of the colon, such as
ulcerative colitis or Crohn's disease.
What are the Symptoms?
Early-stage colorectal cancer might not cause any symptoms, which is why screening is important. When symptoms do appear, they can include:
Changes in bowel habits, such as diarrhea or constipation
Blood in the stool which might make it look dark
Abdominal discomfort or pain
Unexplained weight loss
Weakness or fatigue
Colonoscopy: A procedure that uses a long, flexible tube with a camera to view the inside of the colon and rectum.
Biopsy: During a colonoscopy, if a suspicious area is found, a biopsy can be taken to check for cancer cells.
Imaging Tests: CT scans, MRI, and PET scans can help determine the extent of cancer.
Blood Tests: Tests for specific markers like
CEA (carcinoembryonic antigen) can help in diagnosis and monitoring.
Surgery: Often the primary treatment, especially if the cancer is localized.
Chemotherapy: Uses drugs to destroy cancer cells, often used when cancer has spread.
Radiation Therapy: Uses high-energy rays to kill cancer cells, typically used for rectal cancer.
Targeted Therapy: Drugs that target specific molecules involved in cancer growth.
Immunotherapy: Uses the body's immune system to fight cancer.
Regular Screening: Starting at age 50, or earlier if there are risk factors.
Healthy Diet: High in fruits, vegetables, and whole grains, and low in red and processed meats.
Regular Exercise: Helps maintain a healthy weight and reduces risk.
Avoiding Tobacco and Limiting Alcohol: Both are known risk factors for many cancers.
Managing Health Conditions: Keeping conditions like diabetes and inflammatory bowel disease under control.
What is the Prognosis?
The prognosis for colorectal cancer depends on several factors, including the stage at diagnosis, the patient's overall health, and how well the cancer responds to treatment. Early detection through screening significantly improves the prognosis, with localized cancers often being curable with surgery.
