The case for risk-stratified IORT for early breast cancer.

Despite the significant advancement in local and systemic therapies, breast cancer remains the second leading cause of women cancer deaths ( [1] Siegel RL Miller KD Jemal A. Cancer statistics, 2020. CA Cancer J Clin. 2020; 70 (Jan): 7-30 Crossref PubMed Scopus (11640) Google Scholar ). While adjuvant radiation therapy remains an integral part of breast cancer management ( [2] Darby S McGale P et al. Early Breast Cancer Trialists' Collaborative Group (EBCTCG)Effect of radiotherapy after breast-conserving surgery on 10-year recurrence and 15-year breast cancer death: meta-analysis of individual patient data for 10,801 women in 17 randomised trials. Lancet. 2011; 378: 1707-1716 Abstract Full Text Full Text PDF PubMed Scopus (2428) Google Scholar ), de-escalation strategies are increasingly being investigated. Radiation therapy de-escalation approaches entails fewer treatment days (hypofractionation), smaller target volume (partial breast irradiation -PBI-), or both (accelerated partial breast irradiation -APBI-). More than ten thousand women were enrolled in already reported clinical trials comparing PBI to whole breast radiation therapy (WBRT). PBI can be delivered with different modalities including brachytherapy (BT), external beam radiation therapy, (EBRT), or Intra-operative radiation therapy (IORT). Both American Society of Radiation Oncology (ASTRO) and European Society of Radiation Oncology (ESTRO) published consensus guidelines for APBI ( [3] 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 Abstract Full Text Full Text PDF PubMed Scopus (724) Google Scholar , [4] Polgár C Van Limbergen E Pötter R et al. Patient selection for accelerated partial-breast irradiation (APBI) after breast-conserving surgery: recommendations of the Groupe Européen de Curiethérapie-European Society for Therapeutic Radiology and Oncology (GEC-ESTRO) breast cancer working group based on clinical evidence (2009). Radiother Oncol. 2010; 94: 264-273 Abstract Full Text Full Text PDF PubMed Scopus (490) Google Scholar ). The case against IORT in the management of early stage breast cancerBrachytherapyPreviewSince the development of breast conserving therapy (BCT) that incorporated standard fractionation whole breast irradiation (WBI) delivered daily over 5–7 weeks, there has been a concerted effort to shorten the duration of adjuvant radiation therapy as a way to improve convenience and compliance, reduce costs, and potentially reduce toxicities. Over the past decade, an unprecedent shift in breast radiation techniques and regimens has led to the emergence of shorter courses of WBI (5–15 fractions) as well as partial breast approaches which also reduce treatment duration to 1–3 weeks. Full-Text PDF