Bowel cancer

 Colorectal cancer (CRC), also known as bowel cancer, colon cancer, or rectal cancer, is the development of cancer from the colonor rectum (parts of the large intestine).

Signs and symptoms may include blood in the stool, a change in bowel movements, weight loss, and fatigue. Most colorectal cancers are due to old age and lifestyle factors, with only a small number of cases due to underlying genetic disorders. Risk factors include diet, obesity, smoking, and lack of physical activity. Dietary factors that increase the risk include red meat, processed meat, and alcohol. Another risk factor is inflammatory bowel disease, which includes 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 cancer
Other names	Colon cancer, rectal cancer, bowel cancer
Location and appearance of two example colorectal tumors
Specialty	GastroenterologyGeneral surgeryOncology
Symptoms	Blood in stool, change in bowel movements, unintentional weight loss, vomiting, fatigue[1]
Causes	Old age, lifestyle factors and genetic disorders[2][3]
Risk factors	Diet, obesity, smoking, lack of physical activity, alcohol use[2][4]
Diagnostic method	Tissue biopsy during a sigmoidoscopy or colonoscopy[1]
Prevention	Screening from age of 50 to 75[5]
Treatment	Surgery, radiation therapy, chemotherapy, targeted therapy[6]
Prognosis	Five-year survival rate65% (US)[7]
Frequency	9.4 million (2015)[8]
Deaths	551,000 (2018)[9]

Colorectal 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 whether the disease has spread. Screeningis effective for preventing and decreasing deaths from colorectal cancer. Screening, by one of a number of methods, is recommended starting from the age of 50 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 of pain during polyp excision.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. The five-year survival rate in the United States was around 65% in 2014. 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.Globally, colorectal cancer is the third most common type of cancer, making up about 10% of all cases.In 2018, there were 1.09 million new cases and 551,000 deaths from the disease.It is more common in developed countries, where more than 65% of cases are found. It is less common in women than men.