Published in:
01-03-2016 | Breast Oncology
Locoregional Control According to Breast Cancer Subtype and Response to Neoadjuvant Chemotherapy in Breast Cancer Patients Undergoing Breast-conserving Therapy
Authors:
Shannon K. Swisher, Jose Vila, MD, Susan L. Tucker, PhD, Isabelle Bedrosian, MD, Simona F. Shaitelman, MD, EdM, Jennifer K. Litton, MD, Benjamin D. Smith, MD, Abigail S. Caudle, MD, MPH, Henry M. Kuerer, MD, PhD, Elizabeth A. Mittendorf, MD, PhD
Published in:
Annals of Surgical Oncology
|
Issue 3/2016
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Abstract
Background
Our group previously published data showing that patients could be stratified by constructed molecular subtype with respect to locoregional recurrence (LRR)-free survival after neoadjuvant chemotherapy and breast-conserving therapy (BCT). That study predated use of trastuzumab for human epidermal growth factor receptor 2 (HER2)-positive patients. The current study was undertaken to determine the impact of subtype and response to therapy in a contemporary cohort.
Methods
Clinicopathologic data from 751 breast cancer patients who received neoadjuvant chemotherapy (with trastuzumab if HER2+) and BCT from 2005 to 2012 were identified. Hormone receptor (HR) and HER2 status were used to construct molecular subtypes: HR+/HER2− (n = 369), HR+/HER2+ (n = 105), HR−/HER2+ (n = 58), and HR−/HER2− (n = 219). Actuarial rates of LRR were determined by the Kaplan–Meier method and compared by the log-rank test. Multivariate analysis was performed to determine factors associated with LRR.
Results
The pathologic complete response (pCR) rates by subtype were as follows: 16.5 % (HR+/HER2−), 45.7 % (HR+/HER2+), 72.4 % (HR−/HER2+), and 42.0 % (HR−/HER2−) (P < 0.001). Median follow-up was 4.6 years. The 5-year LRR-free survival rate for all patients was 95.4 %. Five-year LRR-free survival rates by subtype were 97.2 % (HR+/HER2−), 96.1 % (HR+/HER2+), 94.4 % (HR−/HER2+), and 93.4 % (HR−/HER2−) (P = 0.44). For patients with HR−/HER2+ disease, the LRR-free survival rates were 97.4 and 86.7 % for those who did and those who did not experience pCR, respectively. For patients with HR−/HER2− disease, the LRR-free survival rates were 98.6 % (pCR) versus 89.9 % (no pCR). On multivariate analysis, the HR−/HER2− subtype, clinical stage III disease, and failure to experience a pCR were associated with LRR.
Conclusions
Patients undergoing BCT after neoadjuvant chemotherapy have excellent rates of 5-year LRR-free survival that are affected by molecular subtype and by response to neoadjuvant chemotherapy.