Objective: To determine the prevalence, metastatic pattern, and clinical outcomes of patients with each breast cancer subtype stratified according to 2013 St Gallen consensus.
Materials and Methods: We conducted a retrospective descriptive study on breast cancer patients treated in Vajira Hospital from January 1, 2006 to December 31, 2011. Clinico-pathologic data including survival of the patients were collected.
Results: There were 169 breast cancer patients. Seventeen patients were stage I (10.1%), 61 were stage II (36.1%), 65 were stage III (38.5%) and 26 were stage IV (15.4%) at presentation. There were 66 patients (39.1%) classified into Luminal A, 41 patients (24.2%) in Luminal B, 31 patients (18.3%) in HER-2 enriched, and 31 patients (18.3%) in triple-negative subtype, respectively. After median follow-up of 60 months (IQR 26 to 88), the patients in luminal subtypes infrequently recurred and usually had metastatic sites in non-visceral organs, while HER-2 enriched and triple negative usually recurred within the first few years after diagnosis and had metastatic sites in visceral organs.
Conclusion: Stratification of breast cancer patients into subtypes based on 2013 St Gallen Consensus is robust. It is the cheaper and more practical tool compared to molecular techniques.

Keywords: breast cancer, intrinsic subtypes, St Gallen 2013