Treatment outcomes of patients with localized anal squamous cell carcinoma according to HIV infection: systematic review and meta-analysis.

Background: Definitive chemoradiation (CRT) is the standard treatment for localized squamous cell carcinoma of the anus (SCCA). Because most phase III trials in SCCA have excluded patients with HIV, the evidence on treatment outcomes of these patients is lacking. We performed a systematic review and meta-analysis on the efficacy and toxicity profiles of HIV-positive SCCA patients treated with definitive CRT.

Methods: The systematic search was conducted Embase, Medline, Cochrane Libary, Scopus, Lilacs and Opengrey, from inception until September 2017. Eligible studies were clinical trials, prospective or retrospective cohort studies. The main outcome variables were 3-year disease-free survival (DFS) and overall survival (OS) rates and frequency of grade 3 or 4 (G3/4) treatment-related toxicities, according to HIV status. Meta-analyses using pooled risk ratios were performed for binary outcomes from comparative studies from the antiretroviral therapy (HAART) era with the fixed effects model.

Results: Out of 3,951 studies, 40 were deemed eligible, with a total of 3,720 patients. One third (N=1,298; 34%) were HIV-positive and their median pre CRT CD4 count was 347 µm/L. HIV-positive patients presented higher risk of G3/4 cutaneous toxicities [risk ratio (RR) =1.34; 95% CI, 1.10-1.64; P=0.004; I=77.7%], worse 3-year DFS rate (RR =1.32; 95% CI, 1.01-1.74; P=0.043; I=52.19%), and 3-year OS rate (RR =1.77; 95% CI, 1.35-2.32; P<0.001; I=6%).

Conclusions: Patients with localized SCCA and HIV infection treated with CRT tend to experience higher risk of toxicities and worse DFS and OS rates. Our findings suggest that future trials should be tailored to HIV-positive patients.