| Abstract: |
Cancers of the colon, rectum, and anus account for more than 150,000 new cases in the USA each year. The overwhelming majority (approximately 97%) of these are adenocarcinomas of the colon or rectum. Of the 3% that make up the uncommon tumors, approximately half, or 1.5% of the total, will be anal carcinomas (squamous and cloacogenic) and one-third (approximately 1% of the total) will be carcinoid or neuroendocrine tumors. The remaining rare tumors, together comprising about 1% of all large bowel tumors, will be primary intestinal lymphomas, sarcomas, and melanomas. Treatment and prognoses of these tumors vary greatly and will be discussed in this chapter. © 2017 John Wiley & Sons Ltd. |
