Association of HER2/neu subtype with ipsilateral breast tumor recurrence after breast-conserving surgery in young-age breast cancer.

Abstract

e21099 Background: To determine whether breast cancer subtype and age is associated with ipsilateral breast tumor recurrence (IBTR) after breast conserving surgery (BCS). Methods: Using information from Asan medical center and Seoul National University Hospital databases in Korea, we assessed IBTR related to the breast cancer subtype using immunohistochemical (IHC) staining. We also compared the IBTR in young age patients with those in older age patients. Results: In an analysis of 2,235 breast cancer patients who got a breast conserving surgery, 548 patients were ≤40 years old (young age group) and 1,687 patients were over 40 years old (old age group). Median follow up was 61 months. In young age group patients, The Overall 5 year cumulative incidence of IBTR was 2.2%; 1.5% (0.8-2.2) for luminal A, 1.7 % (0.0-3.4) for luminal B, 6.6% (3.0-10.2) for HER2/neu, and 2.8% (1.4-4.2) for triple negative subtype. On multivariate analysis with luminal A as baseline in young age group, only HER2/neu type was associated with increased IBTR (HR=9.9; 95% CI, 1.8-53.3). on Multivariate analysis, IBTR of HER2/neu type of old age group was similar to the those of Luminal A type of young age group (HR 1.04; 95% CI, 0.1-8.3) Conclusions: Overall, the 5 year IBTR after BCS was low, but HER2/neu subtype was associated with increased risk of IBTR only for young breast cancer. future study about the survival effect of IBTR of HER2/neu target agent is warranted.