Estimating the need for palliative radiotherapy for brain metastasis: a benchmarking approach

Palliative radiotherapy (PRT) is useful in the management of many patients with brain metastases, but the need for this treatment in the general cancer population is unknown. The objective of this study was to estimate the appropriate rate of use of PRT for brain metastases (PRT.Br). Ontario's population-based cancer registry was used to identify patients who died of cancer. Radiotherapy records from all the province's radiotherapy centres were linked to Ontario's cancer registry to identify patients who received PRT.Br in the last 2 years of life. Multivariate analysis was used to identify social and health system-related barriers to the use of PRT.Br and to identify a subpopulation of patients with unimpeded access to PRT.Br. The rate of use of PRT.Br was measured in this benchmark subpopulation. The benchmark rate was standardised to the case mix of the overall cancer population. The study population included 231,397 patients who died of cancer in Ontario between 1998 and 2007. Overall, 13,944 patients received at least one course of PRT.Br in the last 2 years of life (6.0%). Multivariate analysis showed that the use of PRT.Br was strongly associated with: the availability of radiotherapy at the diagnosing hospital; the socioeconomic status of the community where the patient lived; and the distance from his/her home to the nearest radiotherapy centre. The benchmark subpopulation was defined as patients diagnosed in a hospital with radiotherapy facilities on site and who resided in a high income community, within 50 km of the nearest radiotherapy centre. The standardised benchmark rate of PRT.Br was 8.0% (95% confidence interval 7.5%, 8.5%). The overall shortfall between the actual rate and the benchmark was 25%, but varied by primary cancer site: lung, 27.6%; melanoma, 19.4%; breast, 13.9%. The magnitude of the shortfall in the use of PRT.Br varied widely across the province. At least 8.0% of patients who die of cancer require PRT.Br at least once in the last 2 years of life, but PRT.Br is widely underutilised in Ontario. The 25% shortfall in the use of PRT.Br reported here is much greater than the previously reported 7.8% shortfall in the overall lifetime rate of use of any radiotherapy in Ontario.