User:Mr. Ibrahem/Colorectal cancer

Colorectal cancer (CRC), also known as bowel cancer, colon cancer, or rectal cancer, is the growth of abnormal cells in the colon or rectum of the large bowel. It has the ability to invade or spread to other parts of the body. Symptoms may include blood in the stool, change in bowel movements, weight loss, feeling tired, and abdominal pain.

Most colorectal cancers are due to old age and lifestyle factors, with only a small number of cases due to underlying genetic disorders. Other risk factors include diet, obesity, smoking, and lack of physical activity. Dietary factors that increase the risk include red meat, processed meat, and alcohol. Other risk factors include radiation treatment to the pelvis, and inflammatory bowel diseases Crohn's disease and ulcerative colitis. Some of the inherited genetic disorders that can cause colorectal cancer include familial adenomatous polyposis and hereditary non-polyposis colon cancer; however, these represent less than 5% of cases. It typically starts as a benign tumor, often in the form of a polyp, which over time becomes cancerous. Colorectal cancers can be generally divided by where in the bowel it occurs; right-sided, left sided and rectal.

Bowel cancer may be diagnosed by obtaining a sample of the colon during a sigmoidoscopy or colonoscopy. This is then followed by medical imaging to determine if the disease has spread. Screening is effective for preventing and decreasing deaths from colorectal cancer. Screening, by one of a number of methods, is recommended starting from the age of 45 to 75. During colonoscopy, small polyps may be removed if found. If a large polyp or tumor is found, a biopsy may be performed to check if it is cancerous. Aspirin and other non-steroidal anti-inflammatory drugs decrease the risk. Their general use is not recommended for this purpose, however, due to side effects.

Treatments used for colorectal cancer may include some combination of surgery, radiation therapy, chemotherapy and targeted therapy. Cancers that are confined within the wall of the colon may be curable with surgery, while cancer that has spread widely is usually not curable, with management being directed towards improving quality of life and symptoms. For early detected local disease, the five-year survival rate is around 90%, but once the cancer has spread, it drops to 14%. The 5-year survival rate in the United States is around 65%. The individual likelihood of survival depends on how advanced the cancer is, whether or not all the cancer can be removed with surgery and the person's overall health.

Colorectal cancer is the most common type of gastrointestinal cancer. In 2020, there were 1.93 million new cases and 916,000 deaths from the disease. It makes up about 10% of all cases. It is the third most frequent cancer in males and second most in females. It is less common in women than men. It is more common in developed countries, where more than 65% of cases are found.