Abstract P2-02-03: Influence of Pre-Operative MRI on the Eligibility for Accelerated Partial Breast Irradiation (APBI)

Abstract

Abstract Purpose: Accelerated partial breast irradiation (APBI) following breast-conserving therapy is currently under investigation in prospective randomized studies. Multifocality and multicentricity are exclusion criteria for APBI. It is proven that pre-operative breast MRI has the ability to dectect ipsilateral and contralateral invasive tumor foci or DCIS in addition to conventional diagnostic methods (clinical examination, mammography and ultrasonography). The objective of this retrospective study was to evaluate the impact of pre-operative MRI on the patient selection for APBI. Patients and methods: From 2002 until 2007 a total of 579 consecutive, non-selected patients with newly-diagnosed early-stage breast cancer received pre-operative Breast MRI in addition to conventional imaging studies at the Bonn University Breast Cancer Center. In total, 130 patients met the criteria for APBI by conventional imaging studies (pathologic tumor size ≥3 cm, negative axillary node status, unifocal disease, no evidence of distant metastases, no invasive lobular carcinoma, lobular carcinoma in situ or Paget's disease). We analyzed the amount of additional ipsi-and contralateral tumor foci detected by MRI. Results: MRI detected additional tumor foci in 7,6 % of patients eligible for APBI (11 tumor foci in 10 out of 130 patients), either ipsilateral (n=7/5,4%) or contralateral (n=4/3.1 %). In one patient MRI found an additional tumor focus both ipsi-and contralateral. Conclusions: Pre-operative breast MRI may be useful for patient selection for APBI. Its ability to identify additional tumor foci in a clinically relevant number of cases may help to avoid undertreatment of these patients. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P2-02-03.