MP11-08 DEVELOPMENT OF A RISK CALCULATOR OF RECURRENCE IN INGUINAL LYMPH-NODE METASTATIC (ILNM) PATIENTS WITH SURGICALLY-RESECTED PENILE SQUAMOUS-CELL CARCINOMA (PSCC)

Abstract

INTRODUCTION AND OBJECTIVE: Inguinal lymph-node metastatic (ILNM) patients (pts) with surgically-resected penile squamous-cell carcinoma (PSCC) tend to have heterogeneous outcomes. We aimed to identify risk factors of early (24-months) cancer recurrence in these pts that can be used for optimizing surveillance strategies and selecting candidates for adjuvant therapies. METHODS: Within an international, multicenter database of 924 men who underwent ILN dissection for a PSCC, we identified 311 ILNM pts. Individuals treated with neoadjuvant chemotherapy (CT) and/or radiotherapy (RT) were excluded. Multivariable Cox regression analyses (MVA) tested for predictors of recurrence, after adjusting for adjuvant therapies, age, type of surgery of the primary and smoking status. As primary endpoint, a risk calculator predicting early (24months) risk of recurrence was developed. As secondary endpoint, the overall survival (OS) benefit of adjuvant therapies was examined according to the risk calculator-derived tertiles using Kaplan-Meier analysis. RESULTS: Overall, 159 pts (51.1%) had pN1-2 and 203 (65.3%) pT2-4 disease. Of all, 195 (62.7%) and 78 (25.1%) received partial or total penectomy, 6 (1.9%) local excision or circumcision and 32 (10.3%) other ablative procedures. Median number of removed and positive ILN were 15 (IQR 9-21) and 2 (IQR 1-3). Pelvic LND was performed in 154 (49.5%) pts, and 39% of them had pelvic LNM. In MVA, % of positive ILNM (HR: 1.01, p= 0.04), pN3 (HR: 2.53, p=0.002) and positive proximal margin of the primary (HR: 2.13, p=0.02) were significantly associated with recurrence. C-index of our 3 variable-risk calculator was 68%, with a net benefit higher that treat-all option from 20% to 90% threshold-probabilities. Within the cohort of adjuvant CT and/or RT (N=127), intermediate-higher tertile pts had similar median OS (NR vs 107m) compared to pts in the lower tertile (p=0.1). Conversely, intermediate-higher tertile pts who received observation alone had shorter OS (NR vs 40m) compared to the same pts in the lower tertile (p=0.0005). Similar results were obtained for CT and RT separately analyzed. CONCLUSIONS: We developed and internally validated a risk calculator for prediction of the early recurrence in ILNM pts with surgically-resected PSCC. According to our risk-calculator, pts with intermediate/higher risk of early recurrence may benefit, with improved OS, from adjuvant therapies. Our risk calculator can be used for counseling and possible enrolment in ongoing studies. Source of Funding: none