Impact of perioperative chemotherapy and radiation for locally advanced penile squamous cell carcinoma (PSCC).

Abstract

4589 Background: While neoadjuvant chemotherapy preceding radical surgery (S) for PSCC appears to provide the most optimal outcomes, there are no randomized studies. The impact of triple-modality S plus perioperative chemotherapy (C) plus radiation (XRT) for PSCC is unclear. The differential outcomes provided by perioperative XRT vs. perioperative C are also unclear. Given the absence of prospective trials, we retrospectively analyzed the U.S. National Cancer Database (NCDB) to study this issue. Methods: Data from the NCDB was obtained for pts with locally advanced PSCC from 1998-2011. Patients who underwent S for PSCC pathologic stage ≥1 with data for receipt of perioperative C and/or XRT and follow-up were eligible for analysis. The following variables were evaluated: pathologic stage, age, Charlson Comorbidity Index (CCI), race, overall survival (OS), socioeconomic status based on median income of area of residence and therapy (S+C, S+XRT, S+C+XRT). Treatment patterns were described. Multivariate analyses (MVA) were conducted to determine the impact of factors on OS with P < 0.05 considered significant. Results: A total of 418 pts were evaluable including 132 in the S+XRT group, 166 in the S+C group and 120 in the S+C+XRT group. The number of pts with stages 1, 2, 3, 4 and unknown were 26, 78, 146, 137 and 31, respectively. In the MVA, stage was independently significantly prognostic (p = 0.002), while age (p = 0.056) and CCI (p = 0.057) were trending significant. S+C+XRT was not statistically better than S+XRT (HR 1.37 [95% CI: 0.935 - 2.007]) or S+C (HR 0.834 [95% CI: 0.589 - 1.180]). Additionally, S+C was not associated with significantly different OS compared to S+XRT (HR 1.142 [95% CI: 0.790 - 1.652]). Limitations of a retrospective analysis apply. Conclusions: This is the largest retrospective study of perioperative therapy for locally advanced PSCC. Triple modality therapy (S+C+XRT) did not extend OS compared to dual modality therapy (S+C or S+XRT). Additionally, the analysis did not identify whether C or XRT should be preferred in pts receiving dual modality therapy. The phase II International Penile Cancer Adjuvant Trial (InPACT) will investigate these conundrums for this orphan malignancy.