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Rectal Cancer Treatment (PDQ®): Treatment - Health Professional Information [NCI] - General Information About Rectal Cancer

Incidence and Mortality

Estimated new cases and deaths from rectal cancer in the United States in 2013:[1]

Recommended Related to Colorectal Cancer

About This PDQ Summary

Purpose of This Summary This PDQ cancer information summary for health professionals provides comprehensive, peer-reviewed, evidence-based information about the treatment of anal cancer. It is intended as a resource to inform and assist clinicians who care for cancer patients. It does not provide formal guidelines or recommendations for making health care decisions. Reviewers and Updates This summary is reviewed regularly and updated as necessary by the PDQ Adult Treatment Editorial...

Read the About This PDQ Summary article > >

  • New cases: 40,340 (rectal cancer only).
  • Deaths: 50,830 (colon and rectal cancers combined).

It is difficult to separate epidemiological considerations of rectal cancer from those of colon cancer because epidemiological studies often consider colon and rectal cancer (i.e., colorectal cancer) together.

Epidemiology

Worldwide, colorectal cancer is the third most common form of cancer. In 2000, colorectal cancer accounted for 9.4% of the world's new cancers, with 945,000 cases diagnosed, and 7.9% of the world's cancer deaths, with 492,000 deaths.[2] Colorectal cancer affects men and women almost equally. Among all racial groups in the United States, African Americans have the highest sporadic colorectal cancer incidence and mortality rates.[3,4]

Adenocarcinomas account for the vast majority of rectal tumors in the United States.[5] Rare tumors, including carcinoid tumors, lymphomas, and neuroendocrine tumors, account for less than 3% of colorectal tumors.[5]

Gastrointestinal stromal tumors can occur in the rectum. (Refer to the PDQ summary on Gastrointestinal Stromal Tumors Treatment for more information.)

Anatomy

The rectum is located within the pelvis, extending from the transitional mucosa of the anal dentate line to the sigmoid colon at the peritoneal reflection; by rigid sigmoidoscopy, the rectum measures between 10 cm and 15 cm from the anal verge.[6] The location of a rectal tumor is usually indicated by the distance between the anal verge, dentate line, or anorectal ring and the lower edge of the tumor, with measurements differing depending on the use of a rigid or flexible endoscope or digital examination.[7] The distance of the tumor from the anal sphincter musculature has implications for the ability to perform sphincter-sparing surgery. The bony constraints of the pelvis limit surgical access to the rectum, which results in a lesser likelihood of attaining widely negative margins and a higher risk of local recurrence.[6]

Risk Factors

Genetic risk factors

Individuals with certain known single-gene disorders are at an increased risk of developing rectal cancer. Single-gene disorders related to known syndromes account for about 10% to 15% of colorectal cancers. (Refer to the PDQ summary on Genetics of Colorectal Cancer for more information.) The hereditary colorectal cancer syndromes and some genes that are involved include:[7,8,9]

Nonpolyposis disorders

  • Hereditary nonpolyposis colorectal cancer (HNPCC) or Lynch syndrome: mismatch repair (MMR) genes.

Polyposis disorders

Hamartomatous disorders

  • Peutz-Jeghers syndrome: STK11/LKB1 gene.
  • Juvenile polyposis syndrome: SMAD4/DPC4 and BMPR1A genes.
  • Cowden syndrome: PTEN gene.
  • Ruvalcaba–Myhre–Smith syndrome: PTEN gene.
  • Hereditary mixed polyposis syndrome.
1|2|3|4|5

WebMD Public Information from the National Cancer Institute

Last Updated: February 25, 2014
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.
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