Epidermal growth factor receptor (EGFR) targeted therapy in advanced metastatic squamous cell carcinoma (AMSCC) of the penis: Updates and molecular analyses.

Abstract

e15022 Background: AMSCC of the penis is a rare but fatal disease. Combination chemotherapy is effective; but responses are brief in duration with few long term survivors. Targeted therapy directed at EGFR has met with success in head and neck squamous cancer. We report a retrospective analysis of patients with AMSCC of the penis patients treated with EGFR targeted therapy at the University of Texas M. D. Anderson Cancer Center. Methods: A retrospective chart review of all patients with AMSCC treated at M. D. Anderson between 2004 and 2006 was performed, and 13 patients were identified who had undergone EGFR expression analysis by immunohistochemistry. The objectives of this study were to determine levels of EGFR expression, additional molecular characteristics, time to progression (TTP) and overall survival (OS). Results: All of the patient tumors (13/13) expressed EGFR with seventy-seven percent exhibiting either “strongly positive” or 3 + levels of expression. The patients received EGFR-targeted therapies including erlotinib (one patient), cetuximab (three patients), or cetuximab combined with platinum based regimens (nine patients). The patients showed a median TTP of 3.2 months (Range 0.37-40.73+ months) and a median OS of 9.8 months (Range 0.5-48.3+ months). The subset of patients receiving EFGR based therapy as first or second line treatment (9/13 patients) showed a median TTP of 3.57 months (Range 1.90-40.73+ months) and median OS of 11.87 months (Range 2.87-48.03+ months). EGFR targeted therapies were well tolerated with grade 1 acne as the most common toxicity. Grade 3 or 4 adverse events included cellulitis, thrombocytopenia, and tumor hemorrhage (one patient each). Additional molecular analyses are ongoing. Conclusions: AMSCC of the penis ubiquitously expressed EGFR. 4/13 patients (31%) treated with EGFR directed therapy survived between 13-48+ months, comparing favorably with the survival previously reported in trials of conventional chemotherapy. Given the results from our retrospective review, we conclude that further studies of EGFR targeted therapies in AMSCC are warranted. No significant financial relationships to disclose.