Oligo-residual disease in PD-1/PD-L1 inhibitor-treated metastatic non-small cell lung cancer: incidence, pattern of failure, and clinical value of local consolidative therapy

To investigate the feasibility and potential clinical value of local consolidative therapy (LCT) in PD-1/PD-L1 inhibitor-treated metastatic non-small cell lung cancer (NSCLC).

PD-1/PD-L1 inhibitor-treated metastatic NSCLC patients with measurable disease in three academic centers were screened and those with adequate follow-up were included. Oligo-residual disease (ORD) was defined as residual tumors limited to three organs and five lesions evaluated at the best response among patients with partial response or stable disease after PD-1/PD-L1 inhibitors. Oligometastatic and multiple-metastatic disease (OMD/MMD) were similarly classified at baseline. Locoregional interventions, administered after effective treatment of PD-1/PD-L1 inhibitors and before initial disease progression, were defined as LCT. Patterns of initial progressive disease (PD) were classified as involving only residual sites (RP), only new sites (NP), or a combination of both (BP).

Among the 698 patients included, ORD was documented in 73 (47.1%) of 155 patients with baseline OMD and 60 (11.0%) of 543 patients with baseline MMD. With a median follow-up of 31.0 (range, 6.0–53.0) months, 108 patients with ORD developed initial PD, with RP, NP, and BP occurring in 51 (47%), 23 (21.3%), and 34 (31.5%), respectively. Among the 133 patients with ORD, those receiving LCT (n = 43) had longer progression-free survival (HR = 0.58, 95% CI 0.40–0.85, p = 0.01) and overall survival (HR = 0.49, 95% CI 0.30–0.79, p < 0.0001).

ORD occurs with a clinically relevant frequency among PD-1/PD-L1 inhibitor-treated metastatic NSCLC patients and LCT may provide extra survival benefits in those with ORD.