Prognostic impact of programmed cell death ligand 1 expression on long‑term oncologic outcomes in colorectal cancer

Abstract

The present study evaluated the association between programmed cell death ligand‑1 (PD‑L1) expression and long‑term oncologic outcomes in colorectal cancer (CRC). PD‑L1 expression was evaluated using immunohistochemistry in 175 patients who underwent surgical resection for CRC between September 1999 and August 2004. Patients were grouped according to PD‑L1 expression, with 82 (46.9%) and 93 (53.1%) in the low and high PD‑L1 expression groups, respectively. The overall survival (OS) and disease‑free survival (DFS) rates were significantly better in the high expression group compared with in the low expression group (OS: 48.2 vs. 32.9%, P=0.047; DFS: 43.3 vs. 32.9%, P=0.021). According to the Tumor‑Node‑Metastasis stage subgroups, the OS rates in the low and high expression groups, respectively, were 66.7 and 60.0% in stage I (P=0.715), 51.8 and 46.7% in stage II (P=0.789), 19.6 and 51.1% in stage III (P=0.011) and 9.1 and 0% in stage IV (P=0.005). The DFS rates in the low and high expression groups, respectively, were 66.7 and 60.0% in stage I (P=0.715), 51.8 and 46.7% in stage II (P=0.857), 19.6 and 38.3% in stage III (P=0.006) and 9.1 and 0% in stage IV (P=0.700). The systemic recurrence rate was significantly higher in the low expression group compared with in the high expression group (42.7 vs. 12.9%, respectively, P=0.030). Low PD‑L1 expression was significantly associated with tumor relapse and poor prognosis in stage III CRC.