Efficacy of radiation boost after breast-conserving surgery for breast cancer with focally positive, tumor-exposed margins.

Kenji Tokumasu,Masahiko Oguchi,Masahiro Yoshida,Ryoko Suzuki,Shinji Ono,Takayuki Ueno,Tomo Osako,Yasuo Yoshioka,Yumi Miyagi

doi:10.1093/jrr/rraa005

Abstract

Many patients with positive margins following breast-conserving surgery (BCS) undergo re-excisions that aim to remove residual disease from the breast, which brings a tremendous emotional burden in addition to financial consequences. We sought to determine whether re-excisions could be safely avoided without compromising local control and survival by using whole-breast radiation therapy (WBRT) with a tumor bed boost in patients with early-stage breast cancer with focally positive, tumor-exposed margins after BCS. All patients with ductal carcinoma in situ (DCIS) and/or invasive breast cancer (IBC) who had pathologically tumor-exposed margins following BCS, without re-excision and treated with WBRT with tumor bed boost between March 2005 and December 2011, were included. The radiotherapy consisted of WBRT at a dose of 50 Gy in 25 fractions, followed by a tumor bed boost with an additional dose of 16 Gy in eight fractions. A total of 125 patients fulfilled the eligibility criteria; of the 125 patients, 1 had bilateral breast cancer, resulting in 126 cases. Invasive disease was found in 102 (81%) cases and purely ductal carcinoma in situ (DCIS) disease in 24 (19%) cases. The 10-year ipsilateral breast tumor recurrence (IBTR) -free survival, progression-free survival (PFS), and 10-year overall survival (OS) rates were 95%, 92.5% and 96%, respectively. Patients with early-stage breast cancer who receive BCS and have focally positive, tumor-exposed margins can avoid re-excision by undergoing WBRT followed by a sufficient dose of tumor bed boost, without negatively impacting local control and survival.

Highlights

Breast-conserving therapy (BCT) comprises complete surgical excision of the primary tumor with a clear margin followed by wholebreast radiation therapy (WBRT)
Insufficient surgical margins might be an indicator for higher rates of recurrence, but re-excisions and redundant margins might result in unnecessary procedures at the cost of a tremendous additional burden for patients
breast-conserving surgery (BCS) is performed by oncological surgeons specializing in breast cancer, who aim to excise a tumor with a 1-cm macroscopic margin

Summary

Introduction

Breast-conserving therapy (BCT) comprises complete surgical excision of the primary tumor with a clear margin followed by wholebreast radiation therapy (WBRT). A considerable proportion of patients undergo re-excisions during attempts to remove residual disease from the breast. The proportion of patients who undergo reexcisions for close and/or positive margins following lumpectomy is 22.9–26%, while the proportion who receive mastectomy is 8.5%– 11.9% [1, 2]. Insufficient surgical margins might be an indicator for higher rates of recurrence, but re-excisions and redundant margins might result in unnecessary procedures at the cost of a tremendous additional burden for patients. The European Organization for Research and Treatment of Cancer (EORTC) ‘boost versus no boost’ trial showed that ipsilateral breast tumor recurrence (IBTR) at 10 years could be reduced with a boost dose of 16 Gy following WBRT in all age groups, tremendous

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