Predictive performance of PD-L1 tumor proportion score for nivolumab response evaluated using archived specimens in patients with non-small cell lung cancer experiencing a postoperative recurrence

Objectives: Postoperative recurrence in patients with non-small-cell lung carcinoma (NSCLC) is a major issue for life expectancy. Programmed cell death ligand 1 (PD-L1) expression on tumor cells is important in the prognosis of NSCLC. However, the predictive ability of PD-L1 evaluated with archived surgical specimens for nivolumab treatment have remained unknown. This study was aimed to analyze the predictive ability of the PD-L1 tumor proportion score (TPS) for nivolumab response in patients with NSCLC experiencing a postoperative recurrence using archived surgical specimens. Materials and methods This retrospective cohort study involved patients with advanced NSCLC (N = 78) treated with nivolumab between April 2016 and September 2018. They were categorized into postoperative recurrence (N = 24) and non-postoperative recurrence (N = 54) groups. The predictive ability of PD-L1 TPS for response to nivolumab treatment in these two groups was determined using receiver operating characteristic (ROC) analysis. Additionally, we evaluated the predictive ability of PD-L1 TPS using rebiopsy specimens collected from the recurrent lesions in six patients of the postoperative recurrence group. Results PD-L1 TPS exhibited lower predictive performance in the postoperative recurrent group (area under the curve [AUC] = 0.58) compared with that in the non-post operative recurrent group (AUC = 0.81). Furthermore, PD-L1 TPS was significantly increased in rebiopsy specimens. The predictive performance of PD-L1 TPS in these specimens was higher (AUC = 0.90) than that in the archived surgical specimens. Conclusions The study revealed that archived surgical specimens are inadequate for assessing the predictive ability of PD-L1 for nivolumab response, while rebiopsy specimes are adequate.