The Open Breast Cancer Journal

2011, 3 : 24-28
Published online 2011 October 18. DOI: 10.2174/1876817201103010024
Publisher ID: TOBCANJ-3-24

The Role of a Boost Radiation Dose in Patients with Negative Re-Excision Findings

Melanie C. Smitt and Kathleen C. Horst
Department of Radiation Oncology, Stanford University, 875 Blake Wilbur Dr, Stanford, CA 94305, USA.

ABSTRACT

The aim of this study is to evaluate whether patients who have no residual tumor at the time of a re-excision lumpectomy benefit from the addition of a radiation boost dose. The records of 535 patients treated with breastconserving therapy (BCT) for Stage I-II breast cancer were reviewed. The actuarial risk of local recurrence (LR) was determined for the 262 patients in this cohort who underwent re-excision lumpectomy. There was no significant difference in the 10-year freedom from local recurrence (FFLR) for patients with negative re-excisions (96%) compared to patients with residual tumor that was adequately excised (92%). Patients with residual tumor at or close to the final margins, however, had a significantly lower FFLR (80%; p=.01). The FFLR for patients with negative re-excisions was 97% for patients not receiving a boost (n=94) and 95% for patients who received a boost (n=74) (p=ns). For patients <50, FFLR was 96% with a boost and 87% without a boost (p=ns). Extensive intraductal component was the only significant predictor of LR among patients with negative re-excisions (p=.02). The presence of residual disease in the re-excision specimen did not predict for LR as long as the final margins were negative. Among patients with negative re-excisions, the boost did not significantly improve local control. There was a trend for better outcomes, however, in younger patients treated with a boost even in the setting of a negative re-excision. Due to the limitations of the retrospective nature of this study, it will be important to address this question in a prospective fashion before making any definitive conclusions or changes in current clinical practice.