Radiotherapy Versus Partial Penectomy for T1 Squamous Cell Carcinoma of the Penis.

Abstract

Radiotherapy (RT) represents an alternative treatment option for patients with T1 squamous cell carcinoma of the penis (SCCP), with proven feasibility and tolerability. However, it has never been directly compared with partial penectomy (PP) using cancer-specific mortality (CSM) as an end point. In the Surveillance, Epidemiology, and End Results database (2000-2020), T1N0M0 SCCP patients treated with RT or PP were identified. This study relied on 1:4 propensity score-matching (PSM) for age at diagnosis, tumor stage, and tumor grade. Subsequently, cumulative incidence plots as well as multivariable competing risks regression (CRR) models addressed CSM. Additionally, the study accounted for the confounding effect of other-cause mortality (OCM). Of 895 patients with T1N0M0 SCCP, 55 (6.1%) underwent RT and 840 (93.9%) underwent PP. The RT and PP patients had a similar age distribution (median age, 70 vs 70 years) and more frequently harbored grade I or II tumors (67.3% vs 75.8%) as well as T1a-stage disease (67.3% vs 74.3%). After 1:4 PSM, 55 (100%) of the 55 RT patients versus 220 (26.2%) of the 840 PP patients were included in the study. The 10-year CSM derived from the cumulative incidence plots was 25.4% for RT and 14.4% for PP. In the multivariable CRR models, RT independently predicted a higher CSM than PP (hazard ratio, 1.99; 95% confidence interval, 1.05-3.80; p = 0.04). For the T1N0M0 SCCP patients treated in the community, RT was associated with nearly a twofold higher CSM than PP. Ideally, a validation study based on tertiary care institution data should be conducted to test whether this CSM disadvantage is operational only in the community or not.