Biological Subtypes and Distant Relapse Pattern in Breast Cancer Patients After Curative Surgery (Study of Anatolian Society of Medical Oncology).

PURPOSE: The aim of the study was to investigate the association between the molecular subtypes and patterns of relapse in breast cancer patients who had undergone curative surgery.

METHODS: We retrospectively evaluated 1,350 breast cancer patients with relapses after curative surgery between 1998 and 2012 from referral centers in Turkey. Patients were divided into 4 biological subtypes according to immunohistochemistry and grade: triple negative, HER2 overexpressing, luminal A and luminal B.

RESULTS: The percentages of patients with luminal A, luminal B, HER2-overexpressing, and triple-negative breast cancer were 32.9% (n = 444), 34.9% (n = 471), 12.0% (n = 162), and 20.2% (n = 273), respectively. The distribution of metastases differed among the subgroups: bone (66.2% and 53.9% in luminal A and B vs. 38.9% in HER2-overexpressing and 45.1% in triple negative, p < 0.001), liver (40.1% in HER2-overexpressing vs. 24.5% in luminal A, 33.5% in luminal B, and 27.5% in triple negative, p < 0.001), lung (41.4% in triple negative and 35.2% in HER2-overexpressing vs. 30.2% and 30.6% in luminal A and B, p = 0.008) and brain (25.3% in HER2-overexpressing and 23.1% in triple negative vs. 10.1% and 15.1% in luminal A and B, p < 0.001).

CONCLUSIONS: Organ-specific metastasis may depend on the molecular subtype of breast cancer. Tailored strategies against distant metastasis concerning the molecular subtypes in breast cancer should be considered.