Correlation between HPV16 positivity on anal swab and biopsy-confirmed HSIL caused by HPV16 in the study of the prevention of anal cancer (SPANC)

Background: The majority of anal carcinomas are caused by human papillomavirus (HPV) 16. Identifying which of the high-grade squamous intraepithelial lesions (HSIL) are caused by HPV16 may enable targeted management of those most likely to progress. Methods: In a natural history study of anal HPV-related lesions in gay and bisexual men, HPV typing of all baseline histologic HSIL was performed utilizing laser capture microdissection (LCM). The results were compared with HPV types detected by Cobas 4800 in matched anal swabs. We calculated the performance of Cobas testing in identifying HSIL caused by HPV16. Results: 158 men had both lesion and swab genotyping. Overall 54 men (34%) had HPV16 identified as the causal genotype of at least one HSIL by LCM. 51 of these had HPV16 detected on their anal swabs (sensitivity of 94%). Of the 104 men with non-HPV16 HSIL biopsies, 73 had swabs negative for HPV16 (specificity of 70%). 51 of 82 men with swabs positive for HPV16 had HPV16 positive biopsies (positive predictive value - 62%). 73 of 76 men without HPV16 detected on their swabs had only non-HPV16 HSIL biopsies (negative predictive value (NPV) - 96%). Conclusions: In men with prevalent histologic HSIL, Cobas testing of a concurrent anal swab has high sensitivity for detecting those with HPV16-associated HSIL and a high NPV. HPV testing with the Cobas platform may have a role in the identification and management of those with HSIL caused by HPV16 and who are at highest risk of development of anal carcinoma