Key clinical point: Patients with estrogen receptor-negative (ER−) primary breast cancer (BC) have a higher risk of developing secondary BC during the first 5 years after treatment than patients with ER-positive (ER+) primary BC.
Major finding: In women with ER− vs ER+ primary BC, the rates of secondary BCs were higher during the first 5 years of follow-up (16.0/1000 person-years [PY]; 95% CI 14.2-17.9/1000 PY vs 7.8/1000 PY; 95% CI 7.3-8.4/1000 PY) but were similar after 5 years (12.1/1000 PY; 95% CI 9.9-14.7/1000 PY vs 9.3/1000 PY; 95% CI 8.4-10.3/1000 PY).
Study details: Findings are from a study including 36,165 women with stage I-III primary BC who underwent breast‐conserving surgery or mastectomy.
Disclosures: This study was funded by the US National Cancer Institute. Some authors declared receiving grants, personal fees, payments, or travel support from several sources.
Source: Lowry KP et al. Variation in second breast cancer risk after primary invasive cancer by time since primary cancer diagnosis and estrogen receptor status. Cancer. 2023 (Feb 15). Doi: 10.1002/cncr.34679