Consolidative Radiotherapy in Oligometastatic Lung Cancer: Patient Selection With a Prediction Nomogram

Patients with stage IV oligometastatic (≤ 3 sites) non-small-cell lung cancer have a progression-free survival (PFS) and overall survival benefit when all sites of metastatic disease and the primary tumor are treated radically with consolidative radiotherapy (cRT). However, the optimal selection of patients most likely from cRT is yet to be defined.

Patients with metastatic non-small-cell lung cancer treated with definitive radiotherapy to all metastatic sites and primary tumor (2008-2019) were retrospectively identified. Univariable Cox proportional-hazards model was used to compare outcomes with demographic and clinical characteristics. A predictive nomogram model for selection of patients most likely to benefit from cRT was constructed.

There were 91 patients identified with a total of 114 metastases treated. Median PFS from the start of cRT was 10.9 months (95% confidence interval [CI], 8.1-16.6), while the median survival time was 37.0 months (95% CI, 31.3-NR). On univariable modeling, patients with squamous histology (hazard ratio, 4.16; 95% CI, 1.99-8.71; P < .001) and those treated with non-stereotactic body radiotherapy hypofractionated therapy (hazard ratio, 5.43; 95% CI, 2.10-14.01; P < .001) had worse overall survival, while patients with targetable mutations (hazard ratio, 0.49; 95% CI, 0.25-0.98; P = .04) had a longer survival. Using a predictive nomogram model, patients with a solitary site of metastasis, targetable mutations, intracranial disease, and metachronous timing of oligometastases had a larger PFS benefit from cRT.

cRT is associated with favorable outcomes in PFS and overall survival. These results may aid in patient counseling, selection for aggressive local therapy, and stratification in future prospective clinical trials.