Brain Metastases among Cancer Patients Diagnosed from 2010-2017 in Canada: Incidence Proportion at Diagnosis and Estimated Lifetime Incidence.

The incidence of BM among Canadian cancer patients is unknown. We aimed to estimate IP of BM at the time of cancer diagnosis and during the lifetime of patients with selected primary cancers. Data on BM at diagnosis from 2010-2017 was obtained from the CCR. Site-specific IPs of BM were estimated from provincial registries containing ≥90% complete data on BM. The CCR IP estimates and the IP estimates from literature were applied to the total diagnosed primary cancers to estimate the number of concurrent BM and lifetime BM from 2010-2017 in Canada, respectively. The annual average number of patients with BM at diagnosis from all cancer sites was approximately 3227. The site-specific IPs of BM at diagnosis were: lung (9.42%; 95% CI: 9.16-9.68%), esophageal (1.58%; 95% CI: 1.15-2.02%), kidney/renal pelvis (1.33%; 95% CI: 1.12-1.54%), skin melanoma (0.73%; 95% CI: 0.61-0.84%), colorectal (0.22%; 95% CI: 0.18-0.26%), and breast (0.21%; 95% CI: 0.17-0.24%). Approximately 76,546 lifetime BM cases (or 5.70% of selected fifteen primary cancers sites) were estimated to have occurred from the 2010-2017 cancer patient cohort. These findings reflect results of population analyses in the US and Denmark. We recommend improved standardization of the collection of BM data within the CCR.