I don’t believe that the available data establish accelerated partial-breast irradiation as equivalent to whole-breast irradiation. Mature 10-year results are needed.
—Jay R. Harris, MD
There is a strong rationale for the use of accelerated partial-breast irradiation: The large majority of in-breast recurrences are at or near the primary site, limiting the radiation dose to the primary site has the potential to decrease side effects, and treatment can be delivered over a shorter period (typically about 1 week). Accelerated partial-breast irradiation can be performed by a variety of techniques, including external-beam (conformal or intensity-modulated) radiation therapy, interstitial multicatheter brachytherapy, intracavitary brachytherapy, or intraoperative radiation, typically at the time of resection of the primary tumor.
In the United States, external-beam radiotherapy is the most frequent technique for accelerated partial-breast irradiation. Most U.S. radiation oncologists are not skilled in the use of interstitial brachytherapy.
The 5-year results of the European GEC-ESTRO trial comparing accelerated partial-breast irradiation and whole-breast irradiation have been reported by Strnad et al1 and are summarized in this issue of The ASCO Post. The results are encouraging, showing no differences in local recurrence, disease-free survival, toxicity, or overall survival with adjuvant accelerated partial-breast irradiation using multicatheter brachytherapy vs whole-breast irradiation in 1,184 women with stage 0, I, or IIA breast cancer undergoing breast-conserving treatment. Results of similar trials are also available from Hungary (258 patients, 10-year results) and Italy (520 patients, 5-year results).2,3 The mature results of the large NSABP/RTOG (National Surgical Adjuvant Breast and Bowel Project/Radiation Therapy Oncology Group) B-32 trial are awaited with keen anticipation but are still pending.
A Word of Caution
I don’t believe that the available data establish accelerated partial-breast irradiation as equivalent to whole-breast irradiation. Mature 10-year results from trials are needed. There is experience in which 5-year results looked promising, but 10-year results manifested problems in both tumor control and toxicity.4 The American Society for Radiation Oncology (ASTRO) published guidelines in 2009 for the use of accelerated partial-breast irradiation, classifying patients as ‘suitable,’ ‘cautionary,’ or ‘unsuitable’ for treatment with accelerated partial-breast irradiation.5 These guidelines are currently being updated, with only minor changes. ■
Disclosure: Dr. Harris reported no potential conflicts of interest.
1. Strnad V, Ott OJ, Hildebrandt G, et al: 5-year results of accelerated partial breast irradiation using sole interstitial multicatheter brachytherapy versus whole-breast irradiation with boost after breast-conserving surgery for low-risk invasive and in-situ carcinoma of the female breast: A randomised, phase 3, non-inferiority trial. Lancet. October 19, 2015 (early release online).
2. Polgár C, Fodor J, Major T, et al: Breast-conserving therapy with partial or whole breast irradiation: Ten-year results of the Budapest randomized trial. Radiother Oncol 108:197-202, 2013.
3. Livi L, Meattini I, Marrazzo L, et al: Accelerated partial breast irradiation using intensity-modulated radiotherapy versus whole breast irradiation: 5-year survival analysis of a phase 3 randomised controlled trial. Eur J Cancer 51:451-463, 2015.
4. Hattangadi JA, Powell SN, MacDonald SM, et al: Accelerated partial breast irradiation with low-dose-rate interstitial implant brachytherapy after wide local excision: 12-year outcomes from a prospective trial. Int J Radiat Oncol Biol Phys 83:791-800, 2012.
5. Smith BD, Arthur DW, Buchholz TA, et al: Accelerated partial breast irradiation consensus statement from the American Society for Radiation Oncology (ASTRO). J Am Coll Surg 209:269-277, 2009.
Dr. Harris is Professor of Radiation Oncology, Department of Radiation Oncology, Dana-Farber Cancer Institute, Brigham and Women’s Hospital, Harvard Medical School, and Chair, Harvard Radiation Oncology Program Executive Committee.
As reported in The Lancet by Vratislav Strnad, MD, of University Hospital Erlangen, Germany, and colleagues, 5-year results of a phase III noninferiority trial showed no difference in local relapse, disease-free survival, or overall survival with adjuvant accelerated partial breast irradiation...