Predictors of anal dysplasia in men who have sex with men with benign cytology.

PURPOSE: Anal cytology is used to screen patients for anal dysplasia. Anal pap smears are collected without direct visualization of the canal, whereas cervical cytology is obtained with direct visualization. Current screening guidelines dictate that patients with abnormal cytology are to be evaluated with high-resolution anoscopy, and patients with benign anal cytology forgo high-resolution anoscopy. We routinely perform standard anoscopy after cytology collection. We endeavored to determine whether our standard procedure would reveal findings supporting high-resolution anoscopy even with benign cytology.
METHODS: We performed a retrospective chart review of all anal cytology results from January 2008 to March 2009, identifying the patients with benign results who had undergone high-resolution anoscopy. Records were analyzed to determine the indication for high-resolution anoscopy and biopsy results.
RESULTS: We identified 2084 patients with anal cytology results, including 613 (29%) patients who had benign results and 169 (28%) patients who had undergone high-resolution anoscopy. The main reasons for high-resolution anoscopy were high risk of recurrent dysplasia based on prior high-grade squamous intraepithelial lesion with cytology done concurrently in 77 (46%), and abnormal anoscopy findings thought to be indicative of dysplasia (plaque or nodule suspicious of dysplasia, internal or external condyloma, dysplastic appearing fissure) in 92 (54%). Of subjects with abnormal anoscopy findings indicative of dysplasia, 25 (27%) had high-grade and 39 (42%) had low-grade dysplasia. Of those undergoing cytology and high-resolution anoscopy simultaneously, 14 (18%) had high-grade and 12 (16%) had low-grade dysplasia. In total, 90 (53%) of those with benign cytology who had high-resolution anoscopy had abnormal pathology, and 39 (23%) had high-grade dysplasia.
CONCLUSIONS: Men having sex with men can have significant dysplasia with benign cytology. Standard anoscopy identifies findings indicative of dysplasia that, if present, should lead to high-resolution anoscopy even with benign cytology. Standard anoscopy should become an integral part of anal dysplasia screening. Prior recent history of high-grade dysplasia should lead to high-resolution anoscopy even with benign cytology.