Abstract
BACKGROUND: Programmed cell death protein 1 (PD-1) blockade plus radiotherapy may be a promising strategy to improve the prognosis of patients with metastatic non-small cell lung cancer (NSCLC). However, the optimum combined scheme, treatment time of radiotherapy, and irradiated lesion have not been fully determined. METHODS: A total of 321 metastatic NSCLC patients treated with immunotherapy were identified. Among them, 107 patients received PD-1/PD-ligand 1 (PD-L1) inhibitors with radiotherapy, while the remaining cases did not receive radiotherapy. Data on overall survival (OS), progression-free survival (PFS), treatment response and adverse events were collected. Comparisons based on type of radiation, timing of radiotherapy and number of irradiated lesions were performed. RESULTS: The median OS in PD-1/PD-L1 inhibitors plus radiotherapy was longer than in nonradiotherapy (22.8 vs. 16.6 months, p = 0.022). The median PFS showed a similar trend in this study (9.4 vs. 6.2 months, p = 0.042). Moreover, the combined strategy demonstrated a superior disease control rate and abscopal control rate versus without radiotherapy (both p ≤ 0.001). Further multivariate analysis in the immunotherapy and radiotherapy groups revealed that age below 65 (p = 0.004), Eastern Cooperative Oncology Group performance scores of 0-1 (p = 0.001), oligometastasis (p = 0.006), concurrent combination (p = 0.002), and treated with SRT (p = 0.013) were associated with longer OS. There was a similar incidence of adverse events between the two groups (both p ≥ 0.05). CONCLUSIONS: The combination of PD-1/PD-L1 inhibitors plus palliative radiotherapy demonstrated favorable survival and good tolerability in metastatic NSCLC patients.