Conditional survival after surgery for patients with penile cancer

Abstract

BACKGROUND: Penile cancer represents a rare pathology whose natural history of treatment is poorly understood. OBJECTIVE: To illustrate the dynamic survival profiles in surgically treated patients with squamous cell carcinoma of the penis (SCCP) using the conditional survival (CS) estimates. MATERIALS AND METHODS: Patients with non-metastatic SCCP were identified from the Surveillance, Epidemiology, and End Results (SEER) database. Conditional 3-yr overall survival (OS) rate and 3-yr cancer-specific survival (CSS) rate represented the primary outcomes of interest and were calculated using the Kaplan-Meier method. The multivariable Cox regression model was employed to calculate proportional hazard ratios for the prediction of mortality. RESULTS: A total of 1887 SCCP patients who had undergone surgeries were identified. Given a 1-, 2-, 3-, 4-, and 5-yr survivorship, the 3-yr OS rates were, respectively, improved by + 9.8 (72.6%), +18.2 (78.1%), +23.4 (81.6%), +27.8 (84.5%), and + 26.6% (83.7%) from those calculated at baseline (time zero). As compared with the baseline calculations, patients who had survived 1, 2, 3, 4, or 5 yr after surgery could, respectively, harvest a + 7.8 (84.7%), +14.8 (90.2%), +19.5 (93.9%), +22.1 (96.0%), and + 22.4% (96.2%) improvement in 3-yr CSS. Patients with the most aggressive disease at baseline ultimately benefited the most from event-free survivorship. Multivariable Cox regression analyses showed that the impact of adverse pathological parameters (G2-3, ≥ pT2, pN+) on OS and CSS mostly showed a decreasing trend over time and some could disappear after a minimum of 1-yr survivorship. DISCUSSION AND CONCLUSION: The survival probability of SCCP patients increases with post-operative survival. Patients with aggressive disease at baseline ultimately benefit the most from event-free survivorship and may expect a better prognosis once they survive the critical few years after surgery. The recorded observations have crucial implications regarding patient counseling and follow-up.