Background:  The incidence of oral cavity and pharynx cancers has been reported to be elevated in individuals with HIV infection. This increase risk among HIV⁺ populations may be due to higher oral human papilloma virus (HPV) prevalence, immunosuppression, and higher prevalence of risk behaviors. However, few studies have been large enough to describe associations with these factors given the rarity of oral cavity/pharynx cancers.

Methods:  This analysis included data from 10 HIV cohorts from the NA-ACCORD. Oral cavity/pharynx cancer cases were validated across cohorts using a standardized process of chart review and cancer registry matching. Incidence was estimated among all HIV⁺ patients without an oral cavity/pharynx cancer diagnosis at baseline. Follow-up ended at the earliest of:  diagnosis or the last reported visit or death. Baseline prevalence and incidence rates of all oral cavity/pharynx cancers were calculated overall and stratified by sex, race, and baseline CD4 cell count (<350 vs ≥350 cells/mL). Direct age standardization of rates was done using the SEER standard population and SEER rates were used to estimate the SIR.

Results:  At baseline there were 8 oral cavity/pharynx cancers among 57,497 HIV⁺ patients resulting in a prevalence of 14 cases per 100,000 people. Among cancer-free patients, 37 incident oral cavity/pharynx cancer were diagnosed yielding a crude incidence rate of 12.6/100,000 person-years (95%CI 9.1 to 17.3) and an age-standardized incidence of 17.5/100,000 person-years (95%CI 11.2 to 23.8). The incidence of oral cavity/pharynx cancer was marginally high among HIV⁺ patients in this study compared to the general US population (SIR 1.3, 95%CI 0.9 to 1.8). The age-standardized rate was significantly higher among those with baseline CD4 <350 cells/mL than CD4 ≥350 (30.1 vs 16.3/100,000 person-years, p = 0.04). Oral cavity/pharynx cancer incidence was 24.9/100,000 person-years in females, 17.4/100,000 person-years in males and 21/100,000 person-years in both blacks and whites (p >0.05 for both comparisons).

Conclusions:  In this large collaboration of North American HIV cohorts, the estimate of oral cavity/pharynx cancer incidence was marginally higher than that noted in the general population. Oral cavity/pharynx cancer incidence was associated with lower CD4 at baseline, suggesting poor immune status or past history of low CD4 may contribute to the increased oral cavity/ pharynx cancer risk among HIV⁺ individuals.