(colorectal cancer) Cancer that develops in the colon (the longest part of the large intestine) and/or the rectum (the last several inches of the large intestine before the anus).

(colorectal cancer) The colon and rectum are part of the large intestine. Colorectal cancer occurs when tumors form in the lining of the large intestine. It is common in both men and women. The risk of developing colorectal cancer rises after age 50. You're also more likely to get it if you have colorectal polyps, a family history of colorectal cancer, ulcerative colitis or Crohn's disease, eat a diet high in fat, or smoke. Symptoms of colorectal cancer include Diarrhea or constipation; A feeling that your bowel does not empty completely; Blood (either bright red or very dark) in your stool; Stools that are narrower than usual; Frequent gas pains or cramps, or feeling full or bloated; Weight loss with no known reason; Fatigue; Nausea or vomiting. Because you may not have symptoms at first, it's important to have screening tests. Everyone over 50 should get screened. Tests include colonoscopy and tests for blood in the stool. Treatments for colorectal cancer include surgery, chemotherapy, radiation, or a combination. Surgery can usually cure it when it is found early. NIH: National Cancer Institute

A malignant epithelial neoplasm that arises from the colon or rectum and invades through the muscularis mucosa into the submucosa. The vast majority are adenocarcinomas.

Lynch syndrome is characterized by an increased risk for colorectal cancer (CRC) and cancers of the endometrium, ovary, stomach, small bowel, urinary tract, biliary tract, brain (usually glioblastoma), skin (sebaceous adenomas, sebaceous carcinomas, and keratoacanthomas), pancreas, and prostate. Cancer risks and age of onset vary depending on the associated gene. Several other cancer types have been reported to occur in individuals with Lynch syndrome (e.g., breast, sarcomas, adrenocortical carcinoma). However, the data are not sufficient to demonstrate that the risk of developing these cancers is increased in individuals with Lynch syndrome.

Colorectal cancer is extremely common. Symptoms include blood in the stool and change in bowel habits. Screening using one of several methods is recommended for appropriate populations. Diagnosis is by colonoscopy. Treatment is surgical resection and chemotherapy for nodal involvement.