HER2-enriched Tumors Have the Highest Risk of Local Recurrence in Chinese Patients Treated with Breast Conservation Therapy

Purpose: The purpose of this study was to investigate the recurrence pattern and characteristics of patientsbased on the 2013 St. Gallen surrogate molecular subtypes after breast-conserving surgery (BCS) in Chinesewomen.
Methods: This retrospective analysis included 709 consecutive breast cancer patients undergoing BCSfrom 1999-2010 at our institution. Five different surrogate subtypes were created using combined expressionof the estrogen receptor, progesterone receptor, and human epidermal growth factor receptor-2. Locoregionalrelapse-free survival (LRRFS), distant metastasis-free survival (DMFS), and disease-free survival (DFS) rateswere calculated.
Results: The 5-year LRRFS, DMFS, and DFS rates were 90.5%, 88.2%, and 81.5%, respectively.Multivariate analysis revealed that young age, node-positive disease, and HER2 enrichment were independentprognostic factors in LRRFS patients. There was also an independent prognostic role of lymph node-positivedisease in DMFS and DFS patients. Patients with luminal A tumors had the most favorable prognosis, withLRRFS, DMFS, and DFS rates of 93.2%, 91.5%, and 87.5% at 5 years, respectively. Conversely, HER-2-enrichedtumors exhibited the highest rate of recurrence (27.5%) and locoregional recurrence (11.4%).
Conclusion:Surrogate subtypes present with significant differences in RFS, DMFS, and LRRFS. Luminal A tumors havethe best prognosis, whereas HER2-enriched tumors have the poorest.