More Confusion on Anal Cancer Screening

March 22, 2012

Paul E. Sax, M.D.

Paul E. Sax, M.D., is director of the HIV Program and Division of Infectious Diseases at Brigham and Women's Hospital in Boston.

Screening for anal cancer in men who have sex with men (MSM) -- with pap smears, high resolution anoscopy, with whatever test -- is quite the quagmire.

As I've mentioned before, the proponents of screening cite the success of cervical cancer screening and the startling high rates of anal cancer among HIV+ MSM as reason enough for doing something.

(Exactly what we should be doing is far from clear.)

The naysayers, who are much less vocal, say there is no evidence that this screening actually reduces the rate of anal cancer, which is of course the endpoint of interest.

Now, over in Lancet Oncology, comes this paper entitled, "Anal human papillomavirus infection and associated neoplastic lesions in men who have sex with men: a systematic review and meta-analysis."

After reviewing a dizzying amount of data, the authors conclude:

Anal HPV and anal cancer precursors were very common in MSM. However, on the basis of restricted data, rates of progression to cancer seem to be substantially lower than they are for cervical pre-cancerous lesions. Large, good-quality prospective studies are needed to inform the development of anal cancer screening guidelines for MSM.

Not to beat a dead horse here, but the fact remains that just because we can screen for pre-cancerous lesions, doesn't mean we should.

(For more on this fascinating dilemma, read this op-ed piece. Or this recent survey.)

And it is notable that two established HIV guidelines -- those for prevention of opportunistic infections and for HIV primary care -- do not endorse anal pap smear screening, awaiting just the sort of prospective studies called for in this paper.

Paul Sax is Clinical Director of Infectious Diseases at Brigham and Women's Hospital. His blog HIV and ID Observations is part of Journal Watch, where he is Editor-in-Chief of Journal Watch AIDS Clinical Care.

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Journal Watch is a publication of the Massachusetts Medical Society.

Reader Comments:

Comment by: Jeff Taylor (Palm Springs, CA) Fri., Apr. 6, 2012 at 10:49 am UTC
As an anal cancer survivor, I can only wish I'd had access fifteen years ago to the anal cancer screening discussed here. I can personally attest that the relatively minor discomfort and cost of treating HGAIN is far less than the four painful & debilitating surgeries I had to undergo to diagnose and treat my in situ squamous cell carcinoma. The horrors experienced by those with invasive disease that requires chemo, radiation & possible resection & colostomy are far worse.

Rather than wring our hands at the dilemma forced on us by the requirements of evidence based medicine (and insurers)--a quandary not extant 50 yrs ago when pap smears dramatically decreased cervical cancer morbidity & mortality, providers should be lobbying the NCI for the large RCT needed to prove the efficacy of anal cancer screening. Telling patients we don't know what to do does them a terrible disservice. We know what needs to be done--providers and KOLs need to lead the way in demanding the research needed to best serve their patients' interest.
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Comment by: Richard G. (San Francisco) Thu., Apr. 5, 2012 at 10:00 am UTC
You have to be kidding.
Perhaps you should go through the nightmare of chemo-radiation for anal cancer, as I did, and see if it was worth it not getting screened early, and treated early. Not even to mention the cost of treatment, but the loss of quality of life as a result of the treatment, what's the cost/benefit analysis of that?
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Replies to this comment:
Comment by: James (London, England.) Thu., Apr. 5, 2012 at 3:46 pm UTC
Good point, Richard. The article almost had me making a note to call my specialist and stop having an annual anal inspection.

Comment by: Nelson Vergel (Houston, Texas United States) Wed., Apr. 4, 2012 at 12:38 am UTC
Anal cancer ranks as the third non AIDS related cancer in the DAD study data. So, no screening? Should we wait for symptoms?

Most doctors do not even do a digital rectal exam to check for growth in the anal canal. This test is low cost and could detect irregularities.

Another problem I am seeing in the field is that hardly any doctor is talking to their young patients (under 26 years of age) about the HPV vaccine.

I know we need controlled data on high resolution anoscopies and IRC's....but many people cannot wait for 5-7 years for that data to be published, assuming that the studies are enrolled.

What do you do in your practice with patients who have been HIV infected of over 15 years, have history of condiloma, and had low CD4 nadir?

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Replies to this comment:
Comment by: James (London, England.) Thu., Apr. 5, 2012 at 3:50 pm UTC
Well said, Nelson. I agree. My annual anal checks are a nuisance, a real "pain in the butt" in terms of inconvenience. But as I have been diagnosed as having pre-cancerous cells in my rectum, it is surely worth my while to have them monitored so as to save myself, if at all possible, the misery that Richard G describes above.

"A stitch in time saves nine."

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