Key clinical point: Patients with human epidermal growth factor receptor 2-positive (ERBB2+) and triple-negative breast cancer (TNBC) are more likely to need radiation for brain metastasis (BRM) than those with other BC subtypes.
Major finding: At the 3-year timepoint, the cumulative incidences of BRM was highest in patients with ERBB2+/hormone receptor-negative (HR−) BC (25.3%). TNBC (hazard ratio 4.25), ERBB2+/HR+ BC (hazard ratio 1.94), and ERBB2+/HR− BC (hazard ratio 2.81; all P < .001) were associated with a shorter time from BC diagnosis to brain radiotherapy than HR+/ERBB2− BC. Patients who received radiotherapy for BRM were more likely to have TNBC or ERBB2+ BC than HR+/ERBB2− BC (P < .001).
Study details: Findings are from a retrospective, observational population-based cohort study including 3916 patients with metastatic BC, of which 31.0% had HR+/ERBB2− BC, 7.9% had ERBB2+/HR+ BC, 5.1% had ERBB2+/HR− BC, and 6.6% had TNBC.
Disclosures: This research was supported by Eli Lilly. Some authors declared serving as consultants, board members, or speakers or receiving grants or personal fees from several sources, including Eli Lilly.
Source: Wang XY et al. Analysis of rates of brain metastases and association with breast cancer subtypes in Ontario, Canada. JAMA Netw Open. 2022;5(8):e2225424 (Aug 12). Doi: 10.1001/jamanetworkopen.2022.25424