Disease-Free Survival and Time to Complete Response After Definitive Chemoradiotherapy for Squamous-Cell Carcinoma of the Anus According to HIV Infection

Abstract

BackgroundThe standard treatment for localized squamous-cell carcinoma of the anal canal is definitive chemoradiotherapy. A meta-analysis of published studies conducted by our group showed significantly lower rates of disease-free survival (DFS) and overall survival at 3 years among HIV-positive patients. We aimed to compare detailed treatment outcomes between the groups of HIV-positive and -negative patients. Patients and MethodsWe performed a retrospective multicenter study of a comparative cohort of consecutive patients with histologic diagnosis of localized squamous-cell carcinoma of the anal canal who received definitive chemoradiotherapy. Patients’ characteristics and outcomes were compared according to HIV status. The primary end points were time to complete response (CR) and DFS time. ResultsFrom June 2001 to September 2018, a total of 185 patients were included; 43 (30.2%) were HIV positive and 142 (69.8%) were HIV negative. The overall CR rates were 67.4% and 91.5% for HIV-positive and -negative patients, respectively (P < .001). The median follow-up was 47.8 months and the median time to experience CR was 7.8 months (95% confidence interval [CI], 5.7-10.5) for HIV-positive versus 4.89 months (95% CI, 4.54-5.25) for HIV-negative (P < .001) patients. The median DFS times were 79.7 months (95% CI, 56.8-102.6) and 127.9 months (95% CI, 112.6-143.2) for HIV-positive and -negative patients, respectively (P = .02). There was a trend toward greater grade 3/4 toxicity in the HIV-positive group. ConclusionHIV-positive patients take longer to experience CR and present worse DFS. These findings have clinical implications because waiting longer to define CR among these patients may prevent unnecessary anorectal amputations.