Efficacy and Toxicity of (Chemo)Radiation Therapy in HIV+ Patients with Squamous Cell Anal Cancer, a Subgroup Analysis of the National Multicenter Cohort FFCD-ANABASE.

Purpose: The influence of human immunodeficiency virus (HIV) infection on clinical outcomes in patients receiving (chemo)radiation therapy (RT) for squamous cell carcinoma of the anus (SCCA) is debated. The objective of this study was to compare efficacy and safety according to HIV status in patients with SCCA treated with C/RT.

Methods And Materials: Between January 2015 and April 2020, 488 patients with a known HIV status (17.6% HIV+) were treated with radiation therapy for SCCA and included in the FFCD-ANABASE multicentric prospective cohort. Clinical outcomes including overall survival (OS), locoregional recurrence-free survival, colostomy-free survival, response rate at 4 to 6 months, cancer-specific survival, relapse-free survival, and severe acute and late toxicity were compared between HIV+ and HIV- patients.

Results: The median follow-up was 35.8 months. HIV+ patients were younger (P < .01) and predominantly male (P < .01). Intensity modulated radiation therapy was performed in 80.7% of patients, and 80.9% received concurrent chemotherapy. A higher proportion of HIV+ patients received induction chemotherapy compared with HIV- patients. No statistically significant difference in overall treatment time or severe acute and late toxicities was found between HIV+ and HIV- patients. In univariate analyses, OS (HR = 2.1 [CI 95% 1.2;3.5], P = .007), locoregional recurrence-free survival (HR = 1.7 [1.1;2.7], P = .02), and colostomy-free survival (HR = 1.7 [1.1;2.6], P = .01) were significantly shorter in HIV+ patients than in HIV- patients. Response rate, cancer-specific survival, and relapse-free survival were not significantly different. The recurrence site was significantly different according to HIV status. In the multivariate analysis, prognostic factors for OS were a World Health Organization performance status of ≥1 for the whole population, as well as HIV+ status for the subgroup of women.

Conclusions: HIV+ patients treated with chemo-RT for SCCA have poorer clinical outcomes, especially women. No difference was found in toxicity according to HIV status with intensity modulated radiation therapy technique.