J Breast Cancer.  2018 Dec;21(4):415-424. 10.4048/jbc.2018.21.e53.

Clinical Differences in Triple-Positive Operable Breast Cancer Subtypes in Korean Patients: An Analysis of Korean Breast Cancer Registry Data

Affiliations
  • 1Division of Breast and Thyroid Surgery, Department of Surgery, Uijeongbu St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Uijeongbu, Korea.
  • 2Division of Breast Surgery, Department of Surgery, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea. wcpark@catholic.ac.kr

Abstract

PURPOSE
Triple-positive breast cancer is defined by estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 (HER2) positivity. Several systemic breast cancer therapies target hormonal and HER2 responsiveness. We compared clinical outcomes of triple-positive disease with those of HER2-enriched and luminal HER2-negative disease and investigated the clinical efficacy of anti-HER2 therapy for triple-positive disease.
METHODS
We retrospectively compared overall and recurrence-free survival among cases included in the Korean Breast Cancer Society (KBCS) and Seoul St. Mary's Hospital breast cancer registries and the therapeutic efficacy of trastuzumab for triple-positive and HER2-enriched cases.
RESULTS
KBCS registry data (2006–2010; median follow-up, 76 months) indicated that patients with triple-positive breast cancer had intermediate survival between those with luminal A and HER2-enriched subtypes (p < 0.001). Trastuzumab did not improve overall survival among patients with triple-positive breast cancer (p=0.899) in contrast to the HER2-enriched subtype (p=0.018). Seoul St. Mary's Hospital registry data indicated similar recurrence-free survival outcomes (p < 0.001) and a lack of improvement with trastuzumab among patients with triple-positive breast cancer (median follow-up, 33 months; p=0.800). Multivariate analysis revealed that patients with triple-positive breast cancer had better overall survival than those with HER2-enriched disease and similar survival as those with the luminal A subtype (triple-positive: hazard ratio, 1.258, p=0.118; HER2-enriched: hazard ratio, 2.377, p < 0.001).
CONCLUSION
Our findings showed that anti-HER2 therapy was less beneficial for treatment of triple-positive breast cancer than for HER2-enriched subtypes of breast cancer, and the triple-positive subtype had a distinct prognosis.

Keyword

Breast neoplasms; ErbB-2 receptor; Estrogen receptors; Hormones; Trastuzumab
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