Incidence and risk factors of HPV-related and HPV-unrelated Head and Neck Squamous Cell Carcinoma in HIV-infected individuals.

OBJECTIVES: To examine the risk and trends of HPV-related and HPV-unrelated Head and Neck Squamous Cell Carcinoma (HNSCC) in HIV-infected individuals and assess whether immunosuppression (measured through CD4 cell count) and other risk factors impact HNSCC risk.

MATERIALS AND METHODS: Incident HNSCCs at HPV-related and HPV-unrelated anatomic sites were detected in HIV-infected participants from pooled data from 17 prospective studies in the North American AIDS Cohort Collaboration on Research and Design (NA-ACCORD) between 1996 and 2009. HNSCC cases were validated using chart review or cancer registry matching. Risk factors for incident HPV-related and HPV-unrelated HNSCC were explored using mixed effects Poisson regression in a full prospective analysis, and the effect of CD4 prior to cancer diagnosis was examined in a nested case control analysis.

RESULTS: 66 HPV-related and 182 HPV-unrelated incident HNSCCs were detected among 82,375 HIV-infected participants. Standardized incidence ratios (SIRs) for both HPV-related (SIR=3.2, 95%CI=2.5-3.4) and HPV-unrelated (SIR=3.0, 95%CI=2.5-4.1) HNSCC were significantly elevated in HIV-infected individuals compared with the US general population. Between 1996 and 2009, the age-standardized HPV-related HNSCC incidence increased non-significantly from 6.8 to 11.4per 100,000 person-years (p-trend=0.31) while the age-standardized incidence of HPV-unrelated HNSCC decreased non-significantly from 41.9 to 29.3 per 100,000 person-years (p-trend=0.16). Lower CD4 cell count prior to cancer diagnosis was significantly associated with increased HPV-related and HPV-unrelated HNSCC risk.

CONCLUSION: The standardized incidence of HPV-related and HPV-unrelated HNSCC are both elevated in HIV-infected individuals. Immunosuppression may have a role in the development of both HPV-related and HPV-unrelated HNSCC.