Effects of antibiotics on immunotherapy in patients with metastatic nonsmall cell lung cancer.

To investigate the effects of antibiotic exposure on the prognosis of patients with advanced metastatic non-small cell lung cancer (m-NSCLC) who received immune checkpoint inhibitors (ICIs). This study retrospectively included 199 patients diagnosed with m-NSCLC in Shandong Cancer Hospital and Institute from December 2017 to October 2021, all patients received ICIs for the first time. The basic clinical characteristics of patients before the first treatment of ICIs, whether antibiotics were used during treatment, progression-free survival (PFS), and overall survival (OS) were collected. The survival among different groups was compared by the Kaplan-Meier method. The median follow-up time of m-NSCLC patients was 33.79 months, mPFS was 11.67 months, and mOS was 21.55 months. Univariate analysis showed that antibiotic use, radiotherapy, and targeted drug resistance influenced PFS and OS ( P  < 0.05). Multivariate analysis showed that antibiotic use, radiotherapy, and targeted resistance remained independent factors of PFS, and targeted resistance was an independent factor of OS ( P  < 0.05). Subgroup analysis found that antibiotic use within 30 days before and after immunotherapy could decrease the PFS and OS ( P  < 0.05). Kaplan-Meier analysis showed that patients without radiotherapy had shorter PFS (mPFS, 12.89 vs. 8.13 months; P  = 0.0258) and OS (mOS, 26.94 vs. 16.43 months; P  = 0.0465). The mPFS (16.17 vs. 9.19 months; P  = 0.0151) and mOS (27.27 vs. 18.65 months; P  = 0.0437) of patients in the antibiotic group were shorter. Patients in the targeted drug-resistant group had shorter PFS (mPFS, 40.66 vs. 7.77 months, P  < 0.001) and OS (mOS, 41.98 vs. 16.89 months, P  < 0.001) compared with patients who did not receive targeted treatment. Antibiotics and radiation therapy are associated with the prognosis of m-NSCLC who are newly treated with ICIs. Effectively reducing antibiotic use in 1 month before and after ICIs treatment may help improve the immunotherapy efficacy of patients with m-NSCLC.