Local ablative treatment for synchronous single organ oligometastatic lung cancer-A propensity score analysis of 180 patients.

INTRODUCTION: Local ablative treatment (LAT) improves outcome in lung cancer with oligometastatic disease (OMD) and potentially leads to long term survival. The aim of this retrospective study was to evaluate and quantify the additional benefit of LAT in synchronous OMD and to further identify prognostic factors for survival.

PATIENTS AND METHODS: A propensity score-matched pairs analysis was performed on a set of patient and disease variables in 180 patients, treated for synchronous single organ OMD including non small-cell and neuroendocrine lung cancer with ≤4 metastases between 2000 and 2016 in 3 lung cancer centers in Berlin, Germany. Patients either received LAT for all sites of disease (intervention group) by means of surgery or stereotactic radiotherapy, or standard chemotherapy, if necessary combined with a local treatment with palliative intent (control group).

RESULTS: Median follow-up time was 32.2 and 18.8 months for the intervention and control group, respectively. Substantial benefits in median progression-free survival (PFS, 25.1 vs. 8.2 months; HR, 0.30; 95% CI, 0.21-0.43; p < 0.001) and overall survival (OS, 60.4 vs. 22.5 months; HR, 0.42; 95% CI, 0.28-0.62; p < 0.001) were associated with LAT. Histology of adenocarcinoma and T1a primaries also predicted a favorable prognosis concerning PFS and OS. More favorable nodal stage (N0-2 vs. 3) and solitary metastases were associated with an extended PFS, whereas initial ECOG-PS (0-1 vs. 2) predicted OS.

CONCLUSIONS: LAT was the strongest predictor for PFS and OS in OMD with ≤4 metastases. Survival in the control group identifies OMD as a subset of lung cancer with a generally more favorable prognosis.