Phase 2 study of pre-excision single-dose intraoperative radiation therapy for early-stage breast cancers

Six-year update with application of the ASTRO accelerated partial breast irradiation consensus statement criteria

Authors

  • Noam A. VanderWalde MD,

    1. Department of Radiation Oncology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
    2. Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
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  • Ellen L. Jones MD, PhD,

    1. Department of Radiation Oncology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
    2. Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
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  • Randall J. Kimple MD, PhD,

    1. Department of Radiation Oncology, University of Wisconsin School of Medicine, Madison, Wisconsin
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  • Dominic T. Moore MPH,

    1. Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
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  • Nancy Klauber-DeMore MD,

    1. Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
    2. Department of Surgery, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
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  • Carolyn I. Sartor MD,

    1. Department of Radiation Oncology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
    2. Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
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  • David W. Ollila MD

    Corresponding author
    1. Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
    2. Department of Surgery, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
    • Department of Surgery, Division of Surgical Oncology and Endocrine Surgery, University of North Carolina at Chapel Hill, 101 Manning Drive, Chapel Hill, NC 27599

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    • Fax: (919) 966-8806


  • All patients who participated in this institutional review board–approved study signed consent prior to accrual on this study.

Abstract

BACKGROUND:

Intraoperative radiation therapy (IORT) allows delivery of high-dose radiation at the time of lumpectomy, potentially sparing adjuvant daily radiation. A phase 2 study of pre-excision IORT was performed for early-stage breast cancer.

METHODS:

Patients ≥ 48 years of age with invasive ductal carcinoma, ≤ 3 cm, and clinically node-negative were eligible for this study, which was approved by institutional review board. Ultrasound was used to select electron energy and cone size to cover the tumor plus 1.5- to 2.0-cm lateral margins and 1-cm-deep margins (90% isodose). Fifteen Gy was delivered with a Mobetron irradiator, and immediate needle-localized partial mastectomy followed. Local event results were updated using the Kaplan-Meier method.

RESULTS:

A total of 53 patients received IORT alone. Median age was 63 years, and median tumor size was 1.2 cm. Of these, 81% were positive for estrogen receptor or progesterone receptor, 11% were positive for human epidermal growth factor receptor 2, and 15% were triple-negative. Also, 42%, 49%, and 9% would have fallen into the Suitable, Cautionary, and Unsuitable groups, respectively, of the American Society of Therapeutic Radiation Oncology consensus statement for accelerated partial breast irradiation. Median follow-up was 69 months. Ipsilateral events occurred in 8 of 53 patients. The 6-year actuarial rate of ipsilateral events was 15% (95% confidence interval = 7%-29%). The crude event rate for Suitable and Cautionary groups was 1 of 22 (5%) and 7 of 26 (27%), respectively. Overall survival was 94.4%, and breast cancer–specific survival was 100%.

CONCLUSIONS:

The rate of local events in this study is a matter of concern, especially in the Cautionary group. On the basis of these findings, pre-excision IORT, as delivered in this study, may not provide adequate local control for less favorable early-stage breast cancers. Cancer 2013. © 2013 American Cancer Society.

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