Important Therapeutic Considerations in T1b Penile Cancer: Prognostic Significance and Adherence to Treatment Guidelines.

Background: The clinical implications and contemporary management of T1b penile cancer are unknown. National treatment guidelines advocate surgical lymph node examination (SLNE) for T1b disease.

Objective: The aim of this study was to evaluate the prognosis of T1b disease and adherence to corresponding treatment guidelines.

Methods: We analyzed 296 patients from two academic centers, and 1263 patients from the Surveillance, Epidemiology, and End Results (SEER) registry (median follow-up 48.3 and 21 months, respectively). Multivariate Cox and Fine-Gray regressions were applied for penile cancer-specific survival (PCSS) analyses.

Results: In the academic center cohort, 28.3% of T1 patients had T1b disease, all of whom underwent SLNE. Nodal metastases were detected in 86.7% of T1b patients and 13.2% of T1a patients (p < 0.001). Using T1a as a reference, PCSS was significantly poorer in the T1b patients, with an adjusted hazard ratio (aHR) of 4.10 (p = 0.03). In the SEER cohort, 16.8% of T1 patients were classified as T1b. SLNE was performed in 21.7% of the T1b patients versus 38.2% of the T2 patients (p = 0.002). The probability of nodal metastases was 2.23-fold higher in T1b patients than in T1a patients (p < 0.001). In clinical N0M0 patients without SLNE, compared with T1a disease, T1b was associated with an aHR of 4.40 and a subdistribution HR of 4.53 for PCSS (both p = 0.003).

Conclusions: T1b penile cancer is strongly associated with nodal metastases and adverse PCSS, and is poorly managed according to guidelines recommended in the nationwide registry.