Minimally invasive lobectomy versus stereotactic ablative radiotherapy for stage I non-small cell lung cancer

A minimally invasive lobectomy (MIL) is the standard treatment for stage I non-small cell lung cancer (NSCLC) in medically operable patients. Stereotactic ablative radiotherapy (SABR) is recommended for inoperable patients and has been proposed as a potential alternative for operable patients as well. Here, we present the results of a feasibility study in preparation for a nationwide retrospective cohort study, comparing outcomes between both treatment modalities.

In this retrospective cohort study, data from patients with clinical stage I NSCLC treated with MIL or SABR in 2014-2015 were retrieved from databases from 12 Dutch hospitals. Progression-free survival (PFS), overall survival (OS) and lung cancer-specific survival (LCSS) were compared between MIL and SABR.

A total of 597 patients with clinical stage I NSCLC treated with MIL (n = 356) or SABR (n = 241) were included. In total, 106 (30%) patients had died in the MIL group and 142 (59%) in the SABR group. After MIL and SABR, unadjusted 5-year PFS was 63% and 30%, OS was 72% and 38% and LCSS was 81% and 76%, respectively. Propensity score-weighted analyses did not show significant differences between MIL and SABR in OS [hazard ratios (HR) 0.74 (95% confidence interval (CI) 0.43-1.29)], PFS [HR 0.74 (95% CI 0.42-1.32)] or LCSS [HR 0.81 (95% CI 0.42-1.59)].

Unadjusted analyses revealed superior OS and PFS for MIL and similar LCSS, but this feasibility study was not sufficiently powered to demonstrate significant differences using propensity score methodology. Therefore, this study is currently being extended to include more than half of Dutch hospitals in order to enlarge the population to ≥1880 patients, not only to determine the best treatment for patients with stage I NSCLC overall, but also to assess the preferred treatment for patient groups with specific characteristics.