👉Conventional whole-breast external beam radiation therapy (EBRT) over 6 weeks is burdensome for many patients, and hypofractionated whole-breast irradiation and accelerated partial breast radiation (APBI) have gained increasing acceptance and appeal as an alternative to EBRT for select groups of patients.
👉In 2016, the American Society for Radiation Oncology (ASTRO) published an updated APBI consensus statement of guidelines regarding which categories of patients are suitable for APBI based on low-risk clinical and tumor characteristics.
👉Patients deemed suitable for APBI were those age 50 years and older with tumors that were T1 (equal or less than 20 mm?, ER-positive, node-negative.
👉Intraoperative radiation therapy is a form of partial breast irradiation that is different from APBI but generally should not be grouped with other APBI modalities.
👉Intraoperative radiation therapy technique differs from APBI and thus has significant differences in terms of outcomes and toxicities.
👉Current guidelines suggest electron IORT may be reasonable in suitable APBI patients while low-energy IORT is recommended on protocol or registry.
👉Two randomized controlled trials of IORT have now been published, the ELIOT trial (which used electrons) and the TARGIT-A trial (which used 50-kV x-rays).
👉With a median follow-up of 5.8 years, the 5-year in-breast recurrence rate in the ELIOT trial was significantly higher in the IORT versus the EBRT group (4.4 vs 0.4%, P=0.001).
👉Similarly, in the TARGIT-A trial, with median 29 months follow-up, in-breast recurrence rate was significantly higher in the IORT versus the EBRT group (3.3 vs 1.3%, P=0.042).
👉Although observed 5-year recurrence rates were lower among a subset of low-risk patients commensurate with ASTRO “suitable” APBI guidelines (1.5%, ELIOT trial), this subset was small and follow-up short.
👉Therefore, recent critical analyses of both the ELIOT and TARGIT trials concluded that IORT should only be offered as part of a strict institutional research protocol and is not yet standard of care for adjuvant post-lumpectomy radiation.
REFERENCES
- Shah C, Vicini F, Wazer D, et al. The American Brachytherapy Society consensus statement for accelerated partial breast irradiation. Brachytherapy. 2013;12:267-277.
- Silverstein MJ, Fastner G, Maluta S, et al. Intraoperative radiation therapy: a critical analysis of the ELIOT and TARGIT trials. Part 1–ELIOT. Ann Surg Oncol. 2014;21:3787-3792.
- Silverstein MJ, Fastner G, Maluta S, et al. Intraoperative radiation therapy: a critical analysis of the ELIOT and TARGIT trials. Part 2–TARGIT. Ann Surg Oncol. 2014;21:3793-3799.
- Smith BD, Arthur DW, Buchholz TA, et al. Accelerated partial breast irradiation consensus statement from the American Society for Radiation Oncology (ASTRO). Int J Radiat Oncol Biol Phys. 2009; 74:987-1001.
- Vaidya JS, Wenz F, Bulsara M, et al; TARGIT Trialists’ Group. Risk-adapted targeted intraoperative radiotherapy versus whole-breast radiotherapy for breast cancer: 5-year results for local control and overall survival from the TARGIT-A randomised trial. Lancet. 2014;383:603-613.
- Veronesi U, Orecchia R, Maisonneuve P, et al. Intraoperative radiotherapy versus external radiotherapy for early breast cancer (ELIOT): a randomised controlled equivalence trial. Lancet Oncol. 2013;14:1269-1277.
Rodrigo Arrangoiz MS, MD, FACScirujano oncology y miembro de Sociedad Quirúrgica S.C en el America British Cowdray Medical Center en la ciudad de Mexico:
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Es experto en el manejo del cáncer de mama.
Rodrigo Arrangoiz MS, MD, FACS, FSSO 