Effect of PD-L1 and tumor regression rate on prognosis of nasopharyngeal carcinoma.

Abstract

To explore the expression level of programmed death ligand-1 (PD-L1) and the tumor regression rate after chemoradiotherapy, and to investigate their influence on the prognosis of patients with nasopharyngeal carcinoma. Eighty-six patients, who were initially diagnosed with non-metastatic nasopharyngeal carcinoma in the Second Xiangya Hospital of Central South University from January 2014 to June 2014, were recruited. Positive expression of PD-L1 in prepared sections of nasopharyngeal carcinoma tissues was detected by immunohistochemical staining. The clinical data of recruited patients and the tumor regression rate were calculated before chemoradiotherapy and 1 month after chemoradiotherapy. In addition, the potential influence of PD-L1 level and the tumor regression rate after chemoradiotherapy on therapeutic efficacy and the prognosis of nasopharyngeal carcinoma were assessed. Among the 86 patients with nasopharyngeal carcinoma, there were 30 patients with high expression of PD-L1 in nasopharyngeal carcinoma sections (34.88%), while there were 56 patients with low expression (65.12%). Expression levels of PD-L1 in nasopharyngeal carcinoma tissues were not related with sex, age, smoking history, concurrent chemoradiotherapy, pathological type, N staging, tumor staging, and pre-treatment EBV-DNA load in peripheral blood in the affected patients (all P>0.05). But the expression level of PD-L1 was related to the tumor regression rate and T staging in the patients with nasopharyngeal carcinoma (both P<0.05). The expression levels of PD-L1 in nasopharyngeal carcinoma tissues was a risk factor for tumor regression rate (OR=0.226, P<0.05). Compared with the patients with low expression levels of PD-L1, there was shorter disease-free survival in the patients with high expression levels of PD-L1 (P<0.05). Moreover, compared with the patients with low tumor regression rate, the nasopharyngeal carcinoma patients with high tumor regression rate showed a favorable disease-free survival (P<0.05). A high expression level of PD-L1 and a low tumor regression rate after chemoradiotherapy are unfavorable to the prognosis of nasopharyngeal carcinoma.