Cervical and Anal Cancer
Source: Physician's First Watch for March 23, 2012
Meta-Analysis: Cervical Cancer Screening Strategies Can't Be Applied to Anal Cancer Prevention
Among men who have sex with men (MSM), rates of progression from high-grade anal intraepithelial neoplasia to anal cancer appear too low to warrant generalized anal cancer screening, according to a meta-analysis in the Lancet Oncology.
The analysis included over 50 studies of anal human papillomavirus (HPV) prevalence and cytological abnormalities among MSM, mostly in North America. The prevalence of high-risk HPV was high (reaching 35% among HIV-positive men), as was the prevalence of high-grade intraepithelial neoplasia (nearly 30% overall). However, using limited data, researchers calculated that the "theoretical" rate of progression from high-grade anal intraepithelial neoplasia to anal cancer was just 1 in 600/year among HIV-positive men and 1 in 4000/year in HIV-negative men.
Noting that "rates of progression to [anal] cancer seem to be substantially lower than they are for cervical pre-cancerous lesions," the researchers conclude that "approaches to cervical cancer screening cannot be simply extrapolated to anal cancer prevention."
And in his HIV and ID Observations blog, Dr. Paul Sax writes: "Just because we can screen for pre-cancerous lesions, doesn't mean we should."
Lancet Oncology article (Free abstract)
Lancet Oncology comment (Subscription required)
Journal Watch HIV and ID Observations blog (Free)
Eva Chalas, MD, FACOG, FACS
ACOG District II Chair
"This article underscores the importance of awareness of the fact that persistent high risk HPV infection can be associate with an increased risk of anal cancer. Digital rectal exam should be a part of the pelvic examination, and if rectal symptoms such as bleeding or change in bowel habits are noted, evaluation with proctoscopy should be recommended."
Mark H. Einstein, MD, MS, FACOG
Albert Einstein College of Medicine and Montefiore Medical Center
His reaction here: