A Single-Institution Experience in the Preoperative Selection of DCIS Patients for IORT using the ASTRO Consensus Guidelines

Abstract

Purpose Intraoperative radiation therapy (IORT) as a form of accelerated partial breast irradiation (APBI) is controversial given the limited evidence to support its efficacy. However, it remains an attractive option for low-risk patients with ductal carcinoma in situ (DCIS), who derive a small absolute benefit in local control with standard whole breast irradiation (WBI). We examine how the American Society for Therapeutic Radiation Oncology (ASTRO) APBI consensus guidelines (CG) may be applied to the preoperative selection of patients with DCIS for IORT and determine treatment outcomes by CG group. Methods and Materials We identified patients with biopsy-proven pure DCIS enrolled in an institutional prospective registry IORT database using the Zeiss Intrabeam ® device between September 2013 and February 2017. Based on available preoperative clinicopathologic information, patients were deemed suitable, cautionary, or unsuitable for IORT according to the ASTRO CG. Change in CG group based on final pathologic diagnosis was determined, and additional therapy was recommended for unsuitable patients. Outcome in terms of ipsilateral breast tumor recurrence was determined. Results A total of 61 DCIS lesions in 60 patients were treated with IORT. Preoperatively, 21 patients (35%) were suitable and 36 (59%) were cautionary. Four (6%) were unsuitable because of lesion size but declined WBI. Final pathologic diagnosis changed the CG grouping of 10 patients (16%) because of either occult high-grade disease in 2 (3%) or close/positive margins in 8 (13%). Ultimately 12 patients total were considered unsuitable, of whom 8 (66%) accepted additional WBI after IORT. At a median follow-up of 2.2 years, ipsilateral breast tumor recurrence was identified among 2 suitable, 1 cautionary, and no unsuitable patients. Conclusion Further investigation is necessary to refine selection of patients with DCIS who may be optimally treated with IORT alone. High acceptance of additional therapy among unsuitable patients resulted in excellent outcomes. The use of biomarkers in addition to traditional clinical and pathologic factors may help to better select patients for IORT.

Global adoption of single-shot targeted intraoperative radiotherapy (TARGIT-IORT) for breast cancer—better for patients, better for healthcare systems

“…TARGIT-IORT is a much more convenient option (28,39). We pointed out that wider availability and applicability of TARGIT-IORT should enable many more women to have the choice of having breast conservation when they would otherwise have a mastectomy because they are not able to have conventional radiotherapy (40)(41)(42)(43)(44)(45)(46)(47)(48)(49). TARGIT-IORT also reduces the cost of providing treatment (50)(51)(52)(53)(54)(55).…”

Intraoperative radiation therapy for early-stage breast cancer: a single-institution experience

“…On univariate analysis, non-IDC histology (i.e., pure DCIS or ILC) was statistically significant in predicting higher IBTR rate. In a retrospective review evaluating adjuvant IORT for treatment of DCIS at a single institution, the 2-year IBTR rate was 4.9% [ 26 ]. Notably, the TARGIT and ELIOT trials excluded DCIS patients from enrollment.…”

Targeted Intraoperative Radiotherapy (TARGIT-IORT) for Early-Stage Invasive Breast Cancer: A Single Institution Experience

“…Herein, we present our single-institution experience with early-stage invasive breast cancer TARGIT-IORT, focusing on changes in group suitability classification determined by ASTRO 2017 APBI CG criteria. Other published single-institution experiences have reported DCIS and early-stage breast cancer TARGIT-IORT treatment outcomes with similar rates of local recurrence as reported in the ELIOT and TARGIT-A trials; however, we further aim to describe the preoperatively determined consensus guideline criteria, breast density classifications, and BMI measurements most likely to result in postoperative group suitability changes and subsequent need for adjuvant WBI ( 13 , 14 ).…”