Comparison of Toxicity and Treatment Outcomes in HIV-positive Versus HIV-negative Patients With Squamous Cell Carcinoma of the Anal Canal

Purpose: To compare the toxicity and treatment outcomes in human immunodeficiency virus (HIV)-positive versus HIV-negative patients with squamous cell carcinoma of the anal canal who underwent definitive concurrent chemoradiation at a single institution. Materials and Methods: Fifty-three consecutive HIV-positive patients treated between 1987 and 2013 were compared with 205 consecutive HIV-negative patients treated between 2003 and 2013. All patients received radiotherapy at a single regional facility. The median radiation dose was 54 Gy (range, 28 to 60 Gy). Concurrent chemotherapy consisted of 2 cycles 5-FU with mitomycin-C given on day 1±day 29). After treatment, patients were closely followed with imaging studies, clinical examinations, and rigid proctoscopies. Outcomes assessed were toxicity rates, progression-free survival, colostomy-free survival, cancer-specific survival, and overall survival. Results: Median follow-up was 34 months. Compared with HIV-negative patients, HIV-positive patients were younger (median age, 48 vs. 62 y) and predominantly male sex (98% of HIV-positive patients were male vs. 22% of HIV-negative patients). Of the HIV-positive patients, 37 (70%) were on highly active antiretroviral therapy, 26 (65%) had an undetectable viral load at the time of treatment, and 36 (72%) had a CD4 count>200 (mean CD4 count, 455). There were no significant differences in acute or late nonhematologic or hematologic toxicity rates between the 2 groups. At 3 years, there was no significant difference between HIV-positive and HIV-negative patients in regards to progression-free survival (75% vs. 76%), colostomy-free survival (85% vs. 85%), or cancer-specific survival (79% vs. 88%, P=0.36), respectively. On univariate analysis, there was a trend toward worse overall survival in HIV-positive patients (72% vs. 84% at 3 y, P=0.06). For the entire cohort, on multivariate analysis only male sex and stage were predictive of worse survival outcomes. HIV status was not associated with worse outcomes in Cox models. Conclusions: In the highly active antiretroviral therapy era, HIV-positive patients with anal cancer treated with standard definitive chemoradiation have equivalent toxicity and cancer-specific survival compared with HIV-negative patients.

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