Comparison of tolerability and efficacy of concurrent chemoradiation (CRT) for anal squamous cell carcinoma (SCC) in HIV-positive (HIV+) and -negative (HIV-) patients (pts)

Abstract

4606 Background: It is believed that the prognosis of anal SCC is poor in HIV+ pts, and their appropriate treatment is uncertain. We compared the tolerability and efficacy of concurrent CRT as definitive therapy for anal SCC in HIV+ and HIV-/unknown pts in the HAART- era. Methods: Pts serially diagnosed and treated in a single institution from Apr/2000 to May/2007. Definitive CRT consisted of 45- 59.4Gy, divided in 5 fractions/week, given with concurrent mitomycin-C (MMC) 15mg/m2D1 IV and 5-fluoruracil (5FU) 1g/m2/d IV, continuous infusion, D1-D4 and D29-D32. Baseline hematologic, hepatic and renal functions were normal in all pts, and the same treatment was delivered irrespective of HIV-status. HIV+ pts were under antiretroviral therapy according to standard recommendations. Results: 78 pts were included in the analysis, median age 56.5y (23–85y), 63 female (81%). Stage: Tis (3 pts), I (4), II (26), IIIA (15), IIIB (20), IV (1). Nine pts were identified as HIV+. HIV+ pts were younger (39.4 vs. 59.2 y, p<0.0001) and predominantly male (8/9 pts). No difference in tumor stage or grade was detected in HIV+ pts. For all pts, the median dose of RT was 45Gy, given over 42d. No difference in terms of treatment duration or administered CRT intensity between HIV+ or HIV- /unknown pts was observed and treatment was well tolerated. Complete response (CR) was achieved in 45 pts (58%), partial response in 7 pts (9%), stable disease in 6 pts (8%) and disease progression in 3 pts (4%). No difference was seen in HIV+ pts in terms of CR rate (6/9 CR (67%), p=0.664). With a mean follow-up of 25mo, 14 deaths have occurred. The median overall survival (OS) was not reached (NR). The 2-y OS rate was 78%. No difference in OS was seen between HIV+ or HIV-/unknown pts (NR in both groups, p=0.248), and a 2-y OS rate of 100% was observed in HIV+ pts. We also observed both longer median PFS (NR vs. 11.5 mo, p=0.0009, HR 0.254, 95%CI 0.034–0.417) and median OS (NR vs. 12.9 mo, p=0.0007, HR 0.180, 95%CI 0.013–0.309) among patients that needed no colostomy. Conclusions: In this group of anal SCC pts no differences in terms of prognosis, treatment tolerance or efficacy could be identified based on HIV status, and the standard 5FU/MMC-based CRT could be delivered successfully. No significant financial relationships to disclose.