Recurrent Metastatic Penile Cancer Patient with Positive PD-L1 Expression Obtained Significant Benefit from Immunotherapy: A Case Report and Literature Review

Penile squamous cell carcinoma (PSCC) bears poor prognosis due to its rarity and limited treatment options, especially after failure of standard treatments. Effective therapeutic options were desperately needed. We report a recurrent metastatic PSCC patient with positive programmed death ligand 1 (PD-L1) expression (≥10%) and tumor mutation burden (TMB) of 8.87 (Muts/Mb) who obtained significant response to immunotherapy, with progression-free survival (PFS) exceeding 10 months. This is the first case presenting remarkable response to immunotherapy in a Chinese PSCC patient. The remarkable response might be associated with PD-L1 expression, indicating that PD-L1 expression could be a promising biomarker for immunotherapy in PSCC. TMB ranking may also contribute to patient selection. However, large clinical trials are needed to validate these notions.