HPV status to predict outcome for anal cancer treated with radiochemotherapy.

4065 Background: Evaluation of the HPV infection- and transformation-status as a predictor of the response to definitive radio-chemotherapy for anal cancer. Methods: 80 patients (54 fm, 26 m) with histologically confirmed anal cancer and known HPV-Infection- (determined by PCR) and p16-expression-status (determined by immunohistochemistry) were analyzed. All pts. were treated with definitive radio-chemotherapy (RCT) with 5-FU/MMC, median age 60ys (35–86), median follow up 54mo (4–180). 41 pts. were HPV+ and p16+ (group 1), 10 pts. were HPV-/p16+ (group 2), 9 pts. were HPV+/p16- (group 3) and 17 pts. were HPV+/p16- (group 4). Endpoints were local control (LC) at 5ys and overall survival (OS) at 5ys. In addition to HPV/p16 status, the influence of T-stage and tumor localization (canal vs. margin) was analyzed. Results: More women than men were HPV+ (fm 77% vs. m 33%) while gender was evenly distributed among HPV-pts. (fm 48% vs. m 53%). Upon univariate analysis, gender, HPV+ and p16+ were significant predic...