Purpose: The aim of this study was to evaluate the chronological changes over 14 years in the survival of Korean patients with breast cancer. We also sought to investigate the factors that may have influenced the changes in survival rate.
Materials and methods: We retrospectively analyzed 17,776 breast cancer patients who were treated at Asan Medical Center between January 2000 and December 2013. Patient information was collected from the Asan database, including age at diagnosis, clinical manifestation, pathology report, types of treatment and modality, types of recurrence, and follow-up period. We classified the patients into two cohorts according to the year of their surgery (P1: 2000-2007 and P2: 2008-2013) and compared survival and recurrence between both cohorts.
Results: We observed that patients treated more recently had better survival outcomes. The 5-year breast cancer-specific survival increased from 94.0% in P1 to 96.6% in P2 (p<0.001), and the 5-year disease-free survival increased from 87.9% in P1 to 91.2% in P2 (p<0.001). When analyzed by type of recurrence, distant metastasis-free survival increased to a significant degree. In subgroup analysis by the subtypes of breast cancer, the survival rates improved in all of the subtypes except triple negative breast cancer, and the improvement was more prominent in subtypes with overexpressed human epidermal growth factor receptor 2.
Conclusion: This study showed improvement in breast cancer survival over the succeeding years, which is consistent with the advancement in systemic therapy.