Cancer Management and Research (Jun 2017)

Tumor cell PD-L1 predicts poor local control for rectal cancer patients following neoadjuvant radiotherapy

  • Shao LD,
  • Peng QQ,
  • Du KX,
  • He JY,
  • Dong YP,
  • Lin XY,
  • Li JL,
  • Wu JX

Journal volume & issue
Vol. Volume 9
pp. 249 – 258

Abstract

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Lingdong Shao,* Qingqin Peng,* Kaixin Du,* Junyan He, Yaping Dong, Xiaoyi Lin, Jinluan Li, Junxin Wu Department of Radiation Oncology, Fujian Medical University Cancer Hospital, Fujian Cancer Hospital, Fuzhou, People’s Republic of China *These authors contributed equally to this work Abstract: The tumor cell (TC) PD-L1 expression has been reported by several studies in various types of cancer, and it reduces the cytotoxicity of T-cells toward cancer and evades the anticancer immune response. Herein, our study focuses on the impact of PD-L1 expression in prognosis and the correlation with clinical prognostic factors for local advanced rectal cancer with neoadjuvant radiotherapy (RT). A total of 68 rectal cancer patients treated with neoadjuvant RT were retrospectively enrolled in the present study. PD-L1 expression was investigated using immunohistochemistry. A regression model was used to identify prognostic factors associated with the disease-free survival, the local recurrence-free survival (LRFS), and the overall survival rates. The median follow-up was 32.5 months. Seven patients presented TC PD-L1 positive (TC PD-L1+), while the others were TC PD-L1 negative (TC PD-L1–). TC PD-L1+ patients showed frequent tumor recurrence than TC PD-L1– patients. Several patients with TC PD-L1– underwent long-course RT. TC PD-L1 expression was similar to interstitial cell (IC) PD-L1 expression, and the relationship between IC PD-L1 and pathological T stage was observed. TC PD-L1+ was related to poor LRFS. The multivariate analysis showed TC PD-L1+ as an independent negative prognostic factor for LRFS. In conclusion, TC PD-L1 expression putatively predicts the LRFS for patients with rectal cancer following neoadjuvant RT. The patients with TC PD-L1+ are susceptible to high local recurrent rate, thereby proposing a novel immunotherapeutic strategy for PD-L1 inhibition-mediated control. Keywords: PD-L1, rectal cancer, neoadjuvant radiotherapy, prognosis 

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