Patterns of distant metastasis in Chinese women according to breast cancer subtypes

// San-Gang Wu 1, * , Jia-Yuan Sun 2, * , Li-Chao Yang 3, * , Li-Ying Tang 4 , Xue Wang 4 , Xue-Ting Chen 4 , Gui-Hua Liu 5 , Huan-Xin Lin 2 , Qin Lin 1 , Zhen-Yu He 2 1 Department of Radiation Oncology, The First Affiliated Hospital of Xiamen University, Xiamen 361003, People’s Republic of China 2 Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Department of Radiation Oncology, Collaborative Innovation Center of Cancer Medicine, Guangzhou 510060, People’s Republic of China 3 Department of Basic Medical Science, Medical College, Xiamen University, Xiamen 361005, People’s Republic of China 4 Eye Institute of Xiamen University, Fujian Provincial Key Laboratory of Ophthalmology and Visual Science, Medical College, Xiamen University, Xiamen 361005, People’s Republic of China 5 School of Pharmaceutical Sciences, Xiamen University, Xiamen 361005, People’s Republic of China * These authors have contributed equally to this work Correspondence to: Qin Lin, email: linqin05@163.com Zhen-Yu He, email: hezhy@sysucc.org.cn Keywords: breast cancer, breast cancer subtype, distant metastasis, patterns Received: December 25, 2015      Accepted: May 20, 2016      Published: June 16, 2016 ABSTRACT To access possible relationships between breast cancer subtypes (BCS) and patterns of distant metastasis in advanced breast cancer. Breast cancer patients with distant metastasis at two academic centers from 2000-2015 were retrospectively reviewed. The breast cancer was classified into four subtypes: hormone receptor (HR) +/ human epidermal growth factor receptor 2 (HER2) − (i.e., estrogen receptor [ER] + and/or progesterone receptor [PR] +, HER2−); HR+/HER2+ (ER+ and/or PR+, HER2+), HR−/HER2+ (ER− and PR−, and HER2+); and HR−/HER2− (ER− and PR−, and HER2−). A total of 679 patients were identified. The distribution of the BCS was 39.9% (271/679), 23.7% (161/679), 16.8% (114/679), and 19.6% (133/679) in HR+/HER2−, HR+/HER2+, HR−/HER2+, and HR−/HER2−, respectively. Patients with HR+/HER2+ and HR−/HER2+ subtypes were prone to abdominal and pelvic metastasis, those with HR+/HER2− and HR+/HER2+ subtypes were prone to bone metastasis, while patients with the HR−/HER2− subtype were prone to lung/mediastinal and brain metastases. In patients with pleural, axillary and/or neck lymph node, and other distant soft tissue metastases, there was no significant difference in metastatic patterns among the BCS. There are different patterns of distant metastasis associated with different BCS. There should be a different focus in the postoperative follow-up and monitoring of breast cancer patients with different BCS.