MP34-04 POST-CHEMOTHERAPY PD-L1 EXPRESSION CORRELATES WITH CLINICAL OUTCOMES IN JAPANESE BLADDER CANCER PATIENTS TREATED WITH TOTAL CYSTECTOMY.

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. 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). 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.) 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.