Negative Predictive Value of Human Papillomavirus Testing: Implications for Anal Cancer Screening in People Living with HIV/AIDS

Objectives. People living with HIV/AIDS (PLWHA) have an increased incidence of anal squamous cell carcinoma. Since high-risk human papillomavirus (hrHPV) is the primary cause, hrHPV DNA testing may play an important role in anal cancer screening. This study aims to determine the negative predictive value (NPV) of hrHPV testing in PLWHA as well as factors that may lead to false-negative results. Methods. Anal swabs were collected for cytology and Cobas (R) 4800 HPV test for 14 hrHPV types. Patients underwent concomitant high-resolution anoscopy (HRA) examination and biopsy. High-grade squamous intraepithelial lesions (HSIL, synonymous with anal intraepithelial neoplasia AIN2 and 3) detected in Cobas-negative patients were genotyped for 22 HPV types using BioPerfectus Multiplex Real-time PCR. Results. 156 PLWHA tested negative for hrHPV on anal swab samples (i.e., Cobas-negative). HRA-guided biopsy detected HSIL/AIN3 in 13 patients (8%, NPV 92%), HSIL/AIN2 in 5 patients (3%), low-grade squamous intraepithelial lesions in 82 (LSIL, 53%), or benign findings in 56 (36%). No cancer was found. The HSIL group was similar to the LSIL/benign group regarding age, gender, race/ethnicity, clinical HIV parameters, cytological diagnoses, history of receptive anal sex, and smoking (p >= 0.02). Genotyping HSIL tissue derived from Cobas-negative patients revealed hrHPV (n=7), possibly carcinogenic HPV53, 67, 73, 82 (n=12), or absence of hrHPV (n=4). Conclusions. In this series, anal hrHPV DNA testing offered 92% NPV for PLWHA; in other words, a 8% risk of occult precancer remains for those who test hrHPV negative on anal swab samples.