Anal Cytologic Testing as a Screening Test – An Institutional Experience
Po Zhao, Abha Goyal. Cleveland Clinic Foundation, Cleveland, OH
Background: Anal carcinoma incidence continues to rise, especially in men who have sex with men. The role of anal cytology in the early detection of high grade anal intraepithelial neoplasia (AIN) is still debatable and currently, there are no national screening guidelines for anal cancer. Here, we describe our anal cytology experience, with regards to the patient population, the distribution of cytologic results, hrHPV (high risk human papillomavirus) detection rates and the histologic outcomes.
Design: A database search was conducted from January 2007 to June 2012 for anal cytologic tests (ThinPrep). Clinical information, the results of concurrent hrHPV testing (Hybrid Capture 2) if available, and histologic follow-up within the next 18 months, if any, were compiled. Also, the development of invasive squamous cell carcinoma during the study period was recorded. Statistical analysis was performed using chi-square test and Fisher's exact test and a p value of < 0.05 was considered as statistically significant.
Results: 443 patients had anal cytologic tests – average age 44.4 years (range 17-80 years), 74% HIV positive (318 men, 4 women), 26% HIV negative (56 men, 65 women). The distribution of cytologic diagnoses is depicted below.
Histologic follow-up was available in 173 (39%) patients. High-grade AIN or above was diagnosed in 30.2% ASC-US, 47.6% LSIL, 77.8% HSIL and 72.2% ASC-H/LSIL-H cases. The difference between the detection rates for high-grade AIN or above in the following groups was not statistically significant – ASC-US vs. LSIL, HSIL vs. ASC-H/LSIL-H and HIV positive vs. HIV negative patients. 76% ASC-US cases were hrHPV positive, of those that were tested. Invasive squamous cell carcinoma was diagnosed in 6 patients – 5 on immediate follow-up and one 33 months following an initial biopsy with AIN2, 3 were HIV positive, cytologic diagnoses included NILM (1), LSIL (2), LSIL-H (2) and HSIL (1).
Conclusions: Our study reveals a high rate of detection of high grade AIN following an abnormal cytology diagnosis and supports the management of patients with lesser cytologic abnormalities (ASC-US/LSIL) with high resolution anoscopy (HRA) and biopsy. Given the high hrHPV positivity rate in the ASC-US group, hrHPV testing may not play a significant role in the triage of these patients to HRA.
Monday, March 4, 2013 1:00 PM
Poster Session II # 84, Monday Afternoon