Hwang WL et al. -Immune checkpoint inhibitors (CPIs) are widely used in the treatment of patients with advanced lung cancer, but are associated with immune-related adverse events (IRAEs).In the current study it was shown that IRAEs, including pneumonitis, are not more common in patients with metastatic lung cancer who received both CPIs and thoracic radiotherapy (TRT).

Methods

• Patients with metastatic lung cancer treated with PD-1/PD-L1 inhibitors were studied. at a US academic medical center.
• IRAEs, including pneumonitis, and survival, were measured from the initiation of CPI therapy.

Results

• 164 patients were included in the analysis.
• Rates of grade 2 or higher IRAEs (13.7% vs. 15.4%), all-grade pneumonitis (8.2% vs. 5.5%), and grade 2 or higher pneumonitis (4.1% vs. 3.3%) were not significantly different between the TRT and non-TRT cohorts.
• The median TRT dose was similar between patients who developed pneumonitis and those who did not (52.8 vs. 50.4 Gy).
• Most patients (57 of 73) were treated with a median TRT dose of 60 Gy (range, 44-79.1 Gy) before CPI initiation (median interval, 8.6 months; range, 0.1-69.0 months).
• None of the 16 patients who received TRT (median/range: 40 Gy, 8-54 Gy) between CPI cycles (n = 5), after CPI (n = 5), or more than 1 course of TRT (n = 6) developed symptomatic pneumonitis.
• The median overall survival was 12.1 months.
• All-cause mortality was significantly lower in patients with grade 2 or higher IRAEs (HR, 0.45) or in patients treated with fewer chemotherapy lines (HR, 1.21).