Prognostic value of PD-L1 combined positive score in patients with upper tract urothelial carcinoma

Purpose Upper tract urothelial carcinoma (UTUC) is relatively rare in Western countries. The impact of programmed death-ligand 1 (PD-L1) expression on UTUC remains unclear because previous studies have focused on bladder UC. We investigated the association of PD-L1 expression with clinicopathological features and prognosis in patients with UTUC. Methods We retrospectively reviewed the patients with UTUC that we treated at our institute from 2013 to 2018. In total, 105 patients with UTUC undergoing radical nephroureterectomy were analyzed to evaluate the PD-L1 expression on representative whole-tissue sections using the Combined Positive Score (CPS; Dako 22C3 pharmDx assay). A PD-L1 CPS >= 10 was considered positive. Results Among the 105 UTUC cases, 17.1% exhibited positive PD-L1 expression. A CPS >= 10 was significantly associated with higher tumor stage (>= T2, p = 0.034) and lymph node invasion at diagnosis (p = 0.021). A multivariable analysis indicated that a CPS >= 10 was an independent prognostic predictor of shorter cancer-specific survival (hazard ratio [HR] = 4.59, 95% confidence interval [CI] = 1.66 - 12.7, p = 0.003) and overall survival (HR = 2.51, 95% CI = 1.19 - 5.27, p = 0.015). Conclusions A PD-L1 CPS >= 10 in UTUC was associated with adverse pathological features and independently predicted worse cancer-specific and overall survival.