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William J. Gradishar, MD, FACP, FASCO
William J. Gradishar, MD, FACP, FASCO
Posted: Monday, October 31, 2022
Petra Grendarova, MD, of The Tom Baker Cancer Centre, Calgary, presented final results from a prospective phase II multicenter trial of accelerated partial breast irradiation (APBI) in patients with early breast cancer at the 2022 American Society for Radiation Oncology (ASTRO) Annual Meeting (Abstract 101). The data described the efficacy and cosmetic outcomes with the use of APBI delivered as intensity-modulated radiotherapy at a dose of 27 Gy in five daily fractions following breast-conserving surgery.
“APBI, using 27 Gy in five fractions using a conformal [intensity-modulated radiotherapy] technique, achieved excellent 2-year cosmesis with minimal toxicity. The ipsilateral breast tumor recurrence risk was comparable to the contralateral new breast cancer risk and to local recurrence rates of recently published early breast cancer trials,” the study authors stated.
The study enrolled 298 patients between April 2016 and October 2019. Women of at least 50 years of age with lymph node–negative, estrogen receptor–positive, HER2-negative breast cancer or ductal carcinoma in situ (up to 3 cm in diameter), following breast-conserving surgery with margins of at least 2 mm, and excellent or good baseline cosmesis, received 27 Gy in five daily fractions to the seroma plus 1 cm clinical target volume and 0.7 cm planning target volume margins. The primary endpoint was the proportion of women who retained excellent or good cosmesis at 2 years using the European Organisation for the Research and Treatment of Cancer (EORTC) Cosmetic Rating System.
At a median follow-up of 48 months, the 4-year overall survival was 98.5% (95% confidence interval [CI] = 96.1%–99.5%) and breast cancer–specific survival was 99.7% (95% CI = 97.6%–99.9%). The 4-year ipsilateral breast tumor recurrence rate was 3.3% (95% CI = 1.1%–6.4%). At 2-year follow-up, most patients had either improved (n = 168; 77%) or experienced no change (n = 43; 20%) in cosmesis, and no patient had cosmetic failure, the authors reported.
Disclosure: Dr. Grendarova reported no conflicts of interest.
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