The utilization patterns and comparative effectiveness of systemic therapy with high-dose thoracic radiotherapy or low-dose thoracic radiotherapy versus systemic therapy alone in newly diagnosed metastatic non-small cell lung cancer patients

Abstract

We used the National Cancer Database (NCDB) to investigate the utilization and effectiveness of high-dose thoracic radiotherapy (RT) with systemic therapy (ST), compared to low-dose RT with ST, or ST alone in patients with metastatic non-small cell lung cancer (mNSCLC), hypothesizing that the use of high-dose thoracic RT with ST would increase in time and be associated with improved overall survival (OS). We identified mNSCLC patients diagnosed between 2004 and 2014 whose initial treatment comprised ST and thoracic RT (ST-RT; n = 46,315) or ST and no thoracic or extrathoracic RT (ST-only; n = 113,009). RT dose was grouped by biologically effective dose (BED10). OS was compared using multivariable regression models and propensity score (PS)–matched analyses. Median follow-up was 9.1 months and 25.8 months among those alive at last follow-up. Among ST-RT patients, 16.9% and 2.3% received BED10 70–99 Gy (n = 7806) and BED10 ≥ 100 Gy (n = 1049), respectively. Compared to the ST-only group, ST-RT patients receiving a BED10 of 40–69 Gy (HR 0.95, p < 0.001), 70–99 Gy (HR 0.69, p < 0.001), or ≥ 100 Gy (HR 0.68, p < 0.001) had improved OS on multivariable analysis, while patients receiving a BED10 of < 40 Gy (HR 1.40, p < 0.001) did not. Patients who received high-dose RT (BED10 ≥ 70 Gy; HD-RT) had improved OS compared to PS-matched controls in the ST-only group (HR 0.68, p < 0.001). Utilization of HD-RT increased year-by-year over the study period. HD-RT utilization increased and was associated with improved OS versus ST alone or ST with low-dose RT. These findings are consistent with results from recently published randomized phase II studies.