BMC Pulmonary Medicine | 2021
Efficacy of immune checkpoint inhibitors in non-small cell lung cancer with uncommon histology: a propensity-score-matched analysis
Abstract
Background Clinical efficacy of immune checkpoint inhibitors (ICIs) for non-small cell lung cancer (NSCLC) with uncommon histology ( u NSCLC) is unknown. Methods Patients with NSCLC treated with ICI monotherapy between January 2014 and December 2018 in 10 Japanese hospitals were retrospectively evaluated. The patients were divided into: (1) NSCLC with common histology ( c NSCLC), defined as adenocarcinoma and squamous cell carcinoma; and (2) u NSCLC, defined as incompatibility with morphological and immunohistochemical criteria for adenocarcinoma or squamous cell carcinoma. Propensity score matching was performed to balance the two groups. Results Among a total of 175 patients included, 44 with u NSCLC (10 pleomorphic carcinomas, 9 large cell neuroendocrine carcinomas, 2 large cell carcinomas, and 23 not otherwise specified) and 44 with matched c NSCLC (32 adenocarcinomas and 12 squamous cell carcinomas) were selected for analyses. Median progression-free survival (PFS) (4.4 months, 95% confidence interval [CI] 1.8–7.7 months) and overall survival (OS) (11.4 months, 95% CI 7.4–27.4 months) in the u NSCLC patients were not significantly different from those in matched c NSCLC patients (5.4 months, 95% CI 3.1–7.6 months, p \u2009=\u20090.761; and 14.1 months, 95% CI 10.6–29.6 months, p \u2009=\u20090.381). In multivariate analysis, Eastern Cooperative Oncology Group performance status (ECOG-PS) of 0–1 and programmed death ligand-1 (PD-L1) expression were predictive for PFS and OS in u NSCLC. Conclusions ICIs had similar clinical efficacy for treatment of u NSCLC and c NSCLC. Good ECOG-PS and PD-L1 expression were predictive for efficacy of ICIs in u NSCLC.