Publications

Abstract

Purpose: To determine whether intrinsic molecular phenotype predicts outcome after breast-conserving therapy (BCT) with lumpectomy and whole breast irradiation with or without a cavity boost. Patients and Methods: 498 patients with invasive breast cancer were enrolled into a randomised trial of BCT with or without a tumour bed radiation boost. Tumors were classified by intrinsic molecular phenotype as luminal A or B, HER-2, basal-like or unclassified using a 5 biomarker panel. Kaplan-Meier and Cox proportional hazards methodology were used to ascertain relationships to ispilateral breast tumour recurrence (IBTR), locoregional recurrence (LRR), distant disease free survival (DDFS) and death from breast cancer. Results: At a median follow-up of 84 months, there were 24 (4.8%) IBTR, 15 (3%) LRR, 47 (9.4%) distant metastases and 37 (7.4%) breast cancer deaths. The overall 5-year disease-free rates for the whole cohort were: IBTR 97.4%, LRR 97.9%, distant metastases 92.9% and breast cancer-specific death 96.3%. A significant difference was observed for survival between subtypes for distant metastases (p=0.0035) and breast cancer-specific death (p=0.0482) but not for IBTR (p=0.346). Conclusion: The 5-year survival rates for all measures of outcome were low, but varied according to molecular subtype using the 5 biomarker panel. Although further follow-up is needed this approach provides additional information to predict time to IBTR, DDFS and death from breast cancer. This augments traditional pathological prognostic indices and may be useful in discussing outcomes and planning management with patients after BCT.