Impact of Immune Checkpoint Inhibitors and Local Radical Treatment on Survival Outcomes in Synchronous Oligometastatic NSCLC.

Introduction: The impact of an immune checkpoint inhibitor (ICI)-based systemic treatment strategy with or without local radical treatment (LRT) on outcomes for patients with NSCLC and synchronous oligometastatic disease (sOMD) is unknown.

Methods: Multicenter retrospective study including adequately staged patients, with sOMD NSCLC (maximum five metastases in three organs [European Organization for Research and Treatment of Cancer definition]) between January 1, 2015 and December 31, 2022, treated with a first-line ICI-based versus chemotherapy-only regimen. Primary end points were progression-free survival and overall survival (OS) for an ICI-based versus chemotherapy-only strategy. Subgroup analyses were performed for patients who were deemed candidates for LRT in the multidisciplinary meeting and those proceeding to LRT.

Results: A total of 416 patients were included, treated with chemotherapy-ICI (n = 138) or chemotherapy-only (n = 278), 319 out of 416 were deemed candidates by multidisciplinary meetings for LRT, whereas 192 (60%) proceeded to LRT. The median OS was significantly longer in the chemotherapy-ICI compared with the chemotherapy-only group (33.6 versus 15.9 mo, hazard ratio [HR] = 0.5, 95% confidence interval [CI]: 0.4-0.7, < 0.001), in the subgroups who were candidate for LRT (36.1 versus 17.2 mo, HR = 0.5, 95% CI: 0.4-0.7, < 0.001) and those proceeding to LRT (not reached versus 23.1 mo, HR = 0.4, 95% CI: 0.2-0.7, < 0.001). In multivariate analysis, an ICI-based strategy was associated with improved survival in the total group (HR = 0.6, 95% CI: 0.4-0.9, < 0.001), in those with intention of LRT (HR = 0.6, 95% CI: 0.4-0.9,  = 0.02) and those who proceeded to LRT (HR = 0.3, 95% CI: 0.1-0.6,  = 0.002).

Conclusions: An ICI-based systemic treatment strategy (±LRT) is associated with improved survival compared with chemotherapy-only (±LRT) for patients with sOMD NSCLC. Prospective randomized trial data are necessary to identify patients most likely to benefit from adding LRT.