Conditional survival after surgery for patients with penile cancer

Penile cancer represents a rare pathology whose natural history of treatment is poorly understood.

To illustrate the dynamic survival profiles in surgically treated patients with squamous cell carcinoma of the penis (SCCP) using the conditional survival (CS) estimates.

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.

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.

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.