Significantly Worse Colostomy-Free Survival in Human Immunodeficiency Virus–Positive Patients After Definitive Chemoradiation for Anal Cancer

Abstract

Human immunodeficiency virus (HIV) status may affect toxicity, disease control and organ preservation after definitive chemoradiation therapy (CRT) for anal cancer. However previous reports are limited by small patient numbers, the use of split course radiation therapy (RT), and patient treated in the pre-HAART era. Here, we report the largest series to date comparing toxicity, disease outcomes and organ preservation between HIV+ and HIV- patients with anal cancer treated with modern RT techniques in the HAART era. We retrospectively reviewed 110 consecutive patients, 39 HIV+, 71 HIV-, who underwent definitive CRT for anal cancer at a single institution between 2004 and 2013. Data on patient characteristics, RT dose and technique, treatment toxicity and treatment outcomes were collected from patient charts. Overall survival (OS), disease-free survival (DFS) and colostomy-free survival (CFS) were investigated. Chi-square test was used to compare frequencies and t-test was used to compare means. Kaplan-Meier survival was calculated and differences were evaluated by Log-rank statistic. Median follow-up was 15 months. HIV+ patients were younger (mean age 51 vs 65, p<.001) and predominantly male (84% vs 16%, p<.005). Five-year OS was 38% in HIV+ and 61% in HIV- (p = .076). Five-year DFS was 28% in HIV+ and 79% in HIV- (p = .074). Five-year CFS was 67% in HIV+ and 88% in HIV- (p = .03). There were no significant differences in T, N, M or stage group. Of 39 HIV+ patients, only 3 (8%) had a CD4 cell count 10 days between HIV+ and HIV- patients (33% vs 27%, p = .487), or in mean number of days beyond expected RT course (13 vs 8 days, p = .20). In this series, HIV+ patients had significantly worse CFS than HIV- patients. While there was no significant difference in OS or DFS, there was a trend towards significance. Delays in starting treatment may contribute to worse outcomes. Acute toxicity and treatment interruptions do not appear to play a role in higher risk of recurrence and salvage surgery. HIV+ patients undergoing treatment for anal cancer should be counseled appropriately regarding the higher risk of colostomy. Further studies are necessary to establish the etiology of this difference, however impaired immune response in HIV+ patients may play a role in difference in outcomes.