What is rectal vs anal cancer?

Very Diff. Cancers: As close as these 2 areas are on the body, the cancers are quite different. Ca of the anus is an aggressive type of skin cancer that, when caught early, responds very well to chemo- and radiation therapy; surgery is rarely needed. Ca of the rectum is very similar to colon ca, arising from the inner intestinal lining; surgery is the main treatment, often preceded by chemo and radiation.

Probably colorectal.: The rectum is really part of the sigmoid colon, and so is usually lumped into the colorectal cancers, while anal cancer constitutes the outer area that can be involved with hemorrhoids, chronic irritation, and anal intercourse. If the anus is involved in colon cancer, or if anal cancer is large, abdominoperianal resection with permanent colostomy may have to be done.

Anatomic location: Anal canal is the last part of the GI tract that connects the rectum to the outside world. Rectum is part just above anal canal. Anal cancers tend to be squamous cell carcinomas, related to hpv as etiology. Rectal cancers are adeno-carcinomas like other colon cancers.