Post-chemotherapy PD-L1 expression correlates with clinical outcomes in Japanese bladder cancer patients treated with total cystectomy.

Abstract

416 Background: Programmed cell death ligand-1 (PD-L1) is a key target molecule of immunotherapy that is frequently overexpressed in bladder cancer. In the present study, we examined whether PD-L1 expression is associated with clinical outcomes in bladder cancer patients. Methods: We enrolled 102 bladder cancer patients treated with cystectomy at the Aomori Prefectural Hospital between April 2004 and May 2014. We conducted an immunohistochemical examination of PD-L1 expression using the SP142 assay. PD-L1 expression was scored at three diagnostic levels (0/1/2). Results: Of the 102 patients, 82 were men (81.0%) and 20 were women (19.0%) (mean age 60 years, range 43-84 years). Sixty-six patients (64.8%) had previously undergone neoadjuvant chemotherapy [neoadjuvant (+) group]. During the mean observation period of 54.5 months, 42 patients had recurring disease (41.1%) and 34 died (33.3%). The 5-year cause-specific survival (CSS) rate was 66.6%; the 5-year disease-free survival (DFS) rate was 59.7%. In the neoadjuvant (+) group, the 5-year DFS rate was 65.0% for PD-L1 (-) patients and 31.7% for PD-L1 (+) patients (log-rank p = 0.006). In the neoadjuvant (+) groups, the 5-year CSS rate was 69.6% for PD-L1 (-) patients and 48.1% for PD-L1 (+) patients. Differences in CSS and DFS rates between PD-L1 (-) and PD-L1 (+) patients in both treatment groups were statistically significant (log-rank p = 0.006 and 0.039, respectively.) Conclusions: Despite the small study size, our data suggest that post-chemotherapy PD-L1 expression is associated with poor prognosis in patients receiving neoadjuvant chemotherapy who had previously undergone cystectomy.