Translating the concept of intrinsic subtypes into an oncoplastic cohort of more than 1000 patients - predictors of recurrence and survival.

ABSTRACT

INTRODUCTION: A paradigm shift in breast cancer was introduced by Sørlie's concept of intrinsic subtypes [1]. We validated this concept - which was originally based on 84 individuals - in a large cohort study of 1035 patients with oncoplastic surgery and analyzed if early and late recurrences are linked to a specific intrinsic tumor subtype or resection margins. MATERIALS AND METHODS: 1035 patients with oncoplastic surgery (2004-2009) were analyzed with regard to treatment characteristics and patterns of early (<5 years) and late recurrence (>5 years) and survival related to the intrinsic subtypes. Data was retrieved from patient's charts, customized patients questionnaires and cancer registries. RESULTS: 944 patients with primary, unilateral breast cancer, median age 58 years, were eligible for analysis. At a median FU of 5.2 years, LRR was 4.0%, 5-year-OS 94.5% and DFS 90.9%. Intrinsic subtypes, but not T-size, nodal-status, resections margins nor histopathology, governed local control and survival. There was no signal for prevelance of unclear margins in any of intrinsic subgroups and no preference of any oncoplastic technique attributed to them. TNBC and Her2 non-luminal breast cancer had highest recurrence and lowest survival rates. Although sentinel involvement (SLN+) was prevailing in the Luminal-B-Her 2 negative subtype at 34.3%, this did not translate into a higher axillary dissection rate. CONCLUSION: This study confirmed the intrinsic subtype concept on a large clinical basis and describes the patterns of early and late recurrence in oncoplastic surgery, concluding that bigger risk may not be overcome by bigger surgery.