PURPOSE:Anal carcinoma is being found in HIV‐positive patients with increasing frequency. Most patients are treated with combined chemotherapy and radiation. It was our impression that HIV‐positive patients do not fare as well as HIV‐negative patients in terms of both response to and tolerance of therapy.METHODS:To test this hypothesis, we reviewed our experience with anal carcinoma and compared HIV‐positive to HIV‐negative patients by age, gender, sexual orientation, stage at diagnosis, treatment rendered, response to treatment, tolerance, and survival. From 1985 to 1998, 98 patients with anal neoplasms were treated. Seventy‐three patients had invasive squamous‐cell carcinoma (including cloacogenic carcinoma), and this cohort was analyzed. Thirteen patients were HIV positive and 60 were HIV negative.RESULTS:The HIV‐positive and HIV‐negative groups differed significantly by age (42vs.62 years,P<0.001), male gender (92vs.42 percent,P<0.001), and homosexuality (46vs.15 percent,P<0.05). There were no differences by stage at diagnosis or radiation dose received. Acute treatment major toxicity differed significantly (HIV positive 80 percentvs.HIV negative 30 percent;P<0.005). Only 62 percent of HIV‐positive patients were rendered disease free after initial therapyvs.85 percent of HIV‐negative patients (P=0.11). Median time to cancer‐related death was 1.4vs.5.3 years (P<0.05). A survival model did not show age, gender, stage, or treatment to be independent predictors.CONCLUSION:We found that HIV‐positive patients with anal carcinoma seem to be a different population from HIV‐negative patients by age, gender, and sexual orientation. They have a poorer tolerance for combined therapy and a shorter time to cancer‐related death. A strong trend to poorer initial response rate was also seen. These results suggest that the treatment of HIV‐positive patients with anal carcinoma needs to be reassessed.