Real-world data on patterns and outcomes of radiation therapy for brain metastases in a population-based cohort of lung cancer patients in Victoria.

Abstract

We evaluated real-world data on the patterns and outcomes of radiotherapy (RT) for brain metastases (BM) in a population-based cohort of patients with lung cancer (LC) in Victoria. The Victorian Radiotherapy Minimum Data set (VRMDS) and the Victorian Cancer Registry (VCR) were linked to identify patients with LC who underwent RT for BM between 2013 and 2016. We determined: (i) proportion of patients treated with stereotactic radiosurgery (SRS); (ii) overall survival (OS); and (iii) 30-day mortality (30M) following RT for BM. Of the 1001 patients included in the study, 193 (19%) had SRS. There was no significant increase in SRS use over time - from 18% in 2013 to 21% in 2016 (P-trend = 0.8). In multivariate analyses, increased age (P = 0.03) and treatment in regional centres (P < 0.001) were independently associated with lower likelihood of SRS treatment. The median OS following RT for BM was 3.6 months. Patients who had SRS had better OS than those who did not have SRS (median OS 8.9 months vs. 3 months, P < 0.01). SRS use, age, sex and year of treatment were independently associated with OS in multivariate analyses. A total of 184 (18%) patients died within 30 days of RT for BM, and the proportion was higher in older (P = 0.001) and male patients (P = 0.004). One-in-five LC patients who received RT for BM had SRS. The improved OS with SRS is likely confounded by patient selection. It is important to reduce 30M by better selecting patients who may not benefit from RT for BM.