Treatment-related adverse events (n = 59).

BackgroundRetrospective evidence indicated potential survival benefit of consolidative stereotactic radiotherapy (SRT) in patients with metastatic driver mutation-negative non-small cell lung cancer (NSCLC) harboring oligo-residual disease (ORD) after effective immune checkpoint inhibitor treatment. However, prospective data about consolidative SRT in this disease population after first-line chemoimmunotherapy remains scarce.Methods and findingsFrom March 2021 to March 2023, 59 patients (94.92% males) with metastatic driver mutation-negative NSCLC harboring ORD after effective first-line chemoimmunotherapy were enrolled in this single-arm, phase 2 trial (NCT04767009), which was conducted at Fudan University Shanghai Cancer Center, Shanghai, China. The median (interquartile range) age was 64 (57,71) years. All of the patients received extracranial and/or cranial SRT covering all of the oligo-residual lesions, without holding the maintenance systemic therapy during SRT. The most common sites targeted by consolidative SRT included the lung (n = 30), lymph nodes (n = 26), bone (n = 22), and brain (n = 22). All efficacy and safety analyses followed the intention-to-treat principle with all 59 enrolled patients included. No patient was lost to follow-up. The primary endpoint was progression-free survival (PFS). Secondary endpoints included overall survival (OS) and treatment-related adverse events (TRAEs). With a median follow-up of 14.8 months, the median PFS was 29.0 (90% CI [13.97, Not Reach]) months, meeting the primary endpoint. The 2-year OS rate was 88.9% (95% CI [75.9%,100%]). TRAEs of any grade and grade ≥3 occurred in 58 (98.31%) and 13 (22.03%) patients, respectively. Moreover, a prespecified propensity score-matched comparison was conducted with a contemporary cohort of patients who developed ORD but received systematic therapy alone, which found that incorporating consolidative SRT was associated with prolonged PFS (adjusted HR 0.286, P P = 0.023). The main methodological limitation of this single-arm trial is its inability to establish causal relationships and the findings require validation in randomized controlled trials.ConclusionsConsolidative SRT was associated with prolonged PFS and generally acceptable toxicities in first-line chemoimmunotherapy-treated patients with metastatic NSCLC harboring ORD, supported by propensity-matched comparisons with a contemporary cohort.