Colon cancer screening guidelines for gay and bisexual men
Gay and bisexual men, and other men who have sex with men (MSM), need to be screened for colon cancer according to the following guidelines:
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At average risk, age 50+ |
Fecal Occult Blood Test (FOBT) at least every two years |
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At high risk |
Colonoscopies starting at age 50, or 10 years before a first-degree relative was diagnosed with colon cancer. People at high risk may have:
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Colon cancer versus anal cancer screening for gay and bisexual men
Many gay and bisexual men, and other men who have sex with men (MSM), are concerned about anal cancer. Their concern is justified, especially for men who are HIV-positive:
- HIV-positive MSM have a high prevalence of HPV-related anal and oral cancers.
- Anal cancer rates are higher among HIV-positive MSM, at approximately 70 per 100,000 people.
- The anal cancer rate among HIV-positive MSM is estimated to be approximately twice that of HIV-negative MSM.
- Overall increases in anal cancer among MSM observed over the past few decades may be related to longer life expectancies in HIV-positive MSM on highly active antiretroviral therapy.
- The National Advisory Committee on Immunization (NACI) recommends MSM receive the quadrivalent human papillomavirus vaccine (HPV) from the age of 9 onwards.
Your gay and bisexual male clients may wonder why Ontario has a province-wide screening program for colon cancer but not for anal cancer. You may need to explain that current evidence shows that screening for colon, breast and cervical cancers is effective at a population level, but that screening for anal cancer is based on an individual client’s medical and personal history and risk factors.
Some health professionals now recommend routine anal cancer screening for HIV-positive and HIV-negative MSM, using an anal Pap test, similar to the Pap test done to detect cervical cell changes in women and trans men. Others refer MSM clients for High Resolution Anoscopy.
Studies show that annual screening of HIV-positive MSM and screening every 2-3 years for HIV-negative MSM provides benefits in both life expectancy and cost effectiveness.
You may want to discuss
risk factors and possible screening for anal
cancer with your male clients who have sex with other men.
Anal Pap tests
- Clients should be instructed to avoid anal sex, douching, and the use of enemas for 24 hours prior to this procedure.
- Use a water-moistened Dacron swab (Baxter Healthcare Corporation) to collect cells prior to anoscopy or anal examination.
- The client is positioned in the left lateral position, and the swab gently inserted until the swab cannot be advanced any further because it has reached the wall of the rectum, thus positioning the swab proximal to the anorectal transformation zone (squamocolumnar junction).
- The swab is then withdrawn with lateral pressure using a spiral motion to sample the entire circumference of the anal canal.
- Since the procedure is performed blindly, cells from the lower rectum, squamocolumnar transformation zone, and anal canal are sampled.
- After removal, the sample may be fixed either conventionally with ethanol or processed using the ThinPrep liquid cytology technique.
The sensitivity in HIV-positive and HIV-negative MSM was 81 and 50 percent and is similar to the sensitivity of cervical cytology.