Bombarding Oligoprogression: Oncologic Outcomes After Radiation to Patients With Oligoprogressive Non-Small Cell Lung Cancer on Maintenance Systemic Therapy.

Objectives: This study aims to evaluate the efficacy and toxicity of radiotherapy (RT) to oligoprogressive metastatic non-small cell lung cancer (NSCLC).

Methods: This is a retrospective analysis of 23 patients with metastatic NSCLC on maintenance systemic therapy, developed oligoprogression (1 to 5 sites), and all oligoprogressive sites amenable to and treated with RT. The primary endpoints included progression-free survival (PFS) and median time to start next-line therapy (MTT). Kaplan-Meier survival analysis and log-rank testing were performed using R-Studio software.

Results: Twenty-three patients met the inclusion criteria. The median overall survival for the entire cohort was 31.3 months (interquartile range [IQR]: 17.86 to 45.4). The median event-free survival for the entire cohort was 8.3 months (IQR: 2.7 to 12). Patients with no prior radiation had longer median event-free survival of 11.9 months (IQR: 8.4 to 18.2) compared with patients with a history of prior radiation at 4.1 months (IQR: 2.7 to 12; P = 0.041). The local control rate for the treated lesions was 97.5%. At 12 months follow-up, 6 (43%) of 14 living patients maintained systemic therapy without initiating next-line therapy. The median PFS for the entire cohort was 8.4 months (IQR: 4.1 to 17.5). Patients who did not receive prior radiation had longer median PFS of 11.9 months (IQR: 8.4 to 18.2) compared with patients who received prior radiation 6.2 months (IQR: 2.7 to 8.5; P = 0.018). Two patients (9%) had grade 3 chronic toxicity related to RT and were medically managed.

Conclusion: We identified that in patients with oligoprogressive metastatic NSCLC, targeted RT to all progressive sites yielded high LC and favorable rates of PFS and MTT.