Implication of programmed cell death ligand 1 expression in tumor recurrence and prognosis in rectal cancer with neoadjuvant chemoradiotherapy

• Published in: International journal of clinical oncology 2016-10, Vol.21 (5), p.946-952
• Main Authors: Saigusa, Susumu, Toiyama, Yuji, Tanaka, Koji, Inoue, Yasuhiro, Mori, Koichiro, Ide, Shozo, Imaoka, Hiroki, Kawamura, Mikio, Mohri, Yasuhiko, Kusunoki, Masato
• Format: Article
• Language: English
• Subjects: Adult; Aged; Aged, 80 and over; Apoptosis; B7-H1 Antigen - analysis; Biomarkers, Tumor - analysis; Cancer Research; CD8-Positive T-Lymphocytes - immunology; Cell Death; Chemoradiotherapy; Chemotherapy; Colorectal cancer; Disease-Free Survival; Female; Forkhead Transcription Factors - analysis; Humans; Lymphatic Metastasis; Lymphocyte Count; Lymphocytes, Tumor-Infiltrating - chemistry; Male; Medical prognosis; Medicine; Medicine & Public Health; Middle Aged; Neoadjuvant Therapy; Neoplasm Invasiveness; Neoplasm Recurrence, Local - chemistry; Oncology; Original Article; Prognosis; Rectal Neoplasms - chemistry; Rectal Neoplasms - pathology; Rectal Neoplasms - therapy; Retrospective Studies; Surgical Oncology; Survival Rate
• ISSN: 1341-9625; 1437-7772
• DOI: 10.1007/s10147-016-0962-4

Background Programmed cell death ligand 1 (PD-L1) regulates immune responses through interaction with its receptor. PD-L1 is not only a predictor of poor prognosis but also a new therapeutic target in several malignancies. Neoadjuvant chemoradiotherapy (CRT) is an effective tool for local control of rectal cancer, but the disease recurrence rate remains high. The aim of this study was to retrospectively evaluate the correlation between PD-L1 expression and clinicopathological variables in rectal cancer after neoadjuvant CRT. Materials and methods A total of 90 rectal cancer patients who underwent neoadjuvant CRT were enrolled in this study. We evaluated PD-L1 expression using immunohistochemistry. Moreover, we investigated the correlation between PD-L1 expression and tumor-infiltrating T cells, and between CD8- and Foxp3-positive cells. Results Patients with high PD-L1 expression more frequently had vascular invasion and tumor recurrence compared to patients with low PD-L1 expression ( P  = 0.0225 and P  = 0.0051). High PD-L1 expression was significantly associated with poor recurrence-free and overall survival ( P  = 0.0027 and P  = 0.0357). Multivariate analysis revealed lymph node metastasis and high PD-L1 expression as independent risk factors for tumor recurrence ( P  = 0.0102 and P  = 0.0374). Numbers of infiltrating CD8-positive cells in patients with high PD-L1 expression were significantly lower than in patients with low PD-L1 expression ( P  = 0.0322). Conclusion Our data suggest that inhibition of PD-L1 may be a new immunotherapeutic strategy to reduce tumor recurrence and improve prognosis in patients with rectal cancer after neoadjuvant CRT.