Risk factors for oropharynx cancer in a cohort of HIV-infected veterans.

Objective: To evaluate HIV-related and other clinical risk factors associated with oropharynx cancer (OPSCC) in HIV-infected U.S. Veterans.

Methods: Retrospective cohort study utilizing Veterans Affairs HIV Clinical Case Registry (CCR) data from 1985 to 2010. Outcome was incident OPSCC as indicated by 1 inpatient or 2 outpatient ICD-9 codes. Cox proportional hazard models were used to determine hazard ratios (HR) and 95% confidence intervals (CI) for each risk factor on the time to OPSCC diagnosis.

Results: A total of 40,996 HIV-infected male veterans were included in the cohort with 97 cases of OPSCC. The age adjusted incidence rate was 23.2/100,000 [95% CI 17.8-29.2]. Age>50 (aHR=3.8, 95% CI 1.9-7.8), recent CD4<200 (aHR=3.8, 95% CI 2.0-7.3), and undetectable HIV viral loads 40-79% of the time (aHR=1.8, 95% CI 1.1-3.0) were associated with an increased risk of OPSCC. Era of HIV diagnosis, utilization of cART, nadir CD4 count, race, smoking history, and previous risk of HPV disease, including condyloma or invasive squamous cell carcinoma of the anus (SCCA) were not associated with increased risk of OPSCC.

Conclusion: Patients who were older at beginning of follow up, had lower CD4 counts around the time of OPSCC diagnosis, and moderate HIV viral control during follow-up had an increased risk of OPSCC. Other HPV-related diseases such as SCCA and condyloma did not increase the risk for OPSCC.