Key clinical point: The development of contralateral breast cancer (CBC) was associated with worsened survival outcomes if the primary breast cancer (PBC) subtype was hormone receptor-positive (HR+)/human epidermal growth factor receptor 2-negative (ERBB2−) or if the patients had CBC onset within 1.5 years after PBC surgery.
Major finding: Compared with patients who did not develop CBC, the risk for death was higher in patients who developed CBC within 1.5 years after PBC surgery (hazard ratio 2.014; P = .04) and in those with HR+/ERBB2− PBC (hazard ratio 1.882; P = .01).
Study details: Findings are from a cohort study including 16,251 patients with stages 0-III PBC, of whom 418 patients developed CBC.
Disclosures: This study did not report any funding source. The authors declared no conflicts of interest.
Source: Kim H et al. Survival after development of contralateral breast cancer in Korean patients with breast cancer. JAMA Netw Open. 2023;6(9):e2333557 (Sep 14). doi: 10.1001/jamanetworkopen.2023.33557