Does High-Risk HPV Genotyping of Abnormal Anal Cytology Improve Detection of High-Grade Anal Intraepithelial Neoplasia (AIN)?
AE Walts, R Chan, P Manna, S Kerley, S Bose. Cedars-Sinai Medical Center, Los Angeles, CA; Physicians Reference Laboratory, Overland Park, KS
Background: High risk (HR) HPV has been established as the major cause of AIN with HPV 16/18 estimated to cause 80% of anal carcinomas. The anal Pap smear is relatively sensitive to detect AIN but has low specificity for predicting and tends to underestimate the severity of AIN observed on biopsy. We sought to determine the prevalence of HR HPV genotypes in anal cytology samples and to assess HR HPV genotyping as an adjunct in diagnosis of individuals with abnormal anal cytology.
Design: 101 anal SurePath samples (28 negative, 25 ASC, 34 LSIL, 6 ASCH, 8 HSIL) from patients 21-74 yrs in age (mean 46.5 yrs; median 46 yrs) were studied. After a Pap stained slide had been prepared from each specimen, DNA was extracted from the residual sample and subjected to multiplex real time PCR utilizing the COMPLeTe Care HPV test (PRL, Overland Park KS) that detects HR HPV 16,18,31,33,35,39,45,51,52, 56,58,59,68,73, and 82. HR HPV genotypes detected in the samples were correlated with concurrent cytodiagnoses and with followup at 1-30 months (mean 3.8 mos; median 4 mos).
Results: HR HPV was detected in 82% of the 101 (50% negative, 84% ASC, and 100% LSIL and above) cases. Multiple (from 2-9) HR HPV genotypes were detected in 71% of the cases. The average number of HR genotypes detected per case increased with severity of cytodiagnosis. HPV 16, present in 44% of all cases and in 53% of the HR HPV+ cases, was the most frequent HR type detected in each diagnostic category. Detection of HPV 16 and 16/18 increased from 21% and 29% respectively in negative up to 75% in HSIL cases. The 66 cases with followup included 25 AIN 2/3 and 18 AIN 1. 20 of the 25 AIN 2/3 were preceded by HPV 16/18+ cytology. 46% of the HPV16/18+ LSIL cases and 22% of the HPV 16/18+ ASC cases showed AIN 2/3 at followup. No genotype predominated among the non16/18 HR HPV+ cytology samples that showed AIN 2/3 at followup.
Conclusions: -The overall high prevalence of HR HPV detected in 82% of anal cytology samples from persons at increased risk for AIN indicates that screening for HR HPV is not efficacious in diagnosis of AIN 2/3 in this population. -80% of the AIN 2/3 at followup were preceded by HPV 16/18+ anal cytology. 39% of HPV 16/18+ ASC/LSIL samples showed AIN 2/3 at followup compared to 18% of the non16/18 HR HPV+ and HR HPV- ASC/LSIL cases. Testing for HPV 16/18 may help select cases for aggressive management.
Tuesday, March 23, 2010 9:30 AM
Poster Session III # 87, Tuesday Morning