Intraoperative radiotherapy boost as part of breast-conservation therapy for breast cancer: a single-institution retrospective analysis

Abstract

Background There are currently no data from randomized controlled trials on the use of intraoperative radiotherapy (IORT) as a tumor bed boost as part of a breast-conservation approach for breast cancer. This study retrospectively reviewed the safety and efficacy of IORT as a boost treatment at a tertiary cancer center. Methods From 2015 to 2019, patients underwent breast-conserving surgery with axillary lymph node staging and a single dose of 20 Gy IORT with 50-kV photons, followed by whole-breast irradiation (WBI) and adjuvant systemic therapy (if applicable). Patients were followed for assessment of acute and late toxicities (using the Common Terminology Criteria for Adverse Events version 5.0) at 3–6-month intervals. Outcomes included ipsilateral (IBTR) and contralateral breast progression-free survival (CBE), distant metastasis-free survival (DMFS), and overall survival (OS). Results Median follow-up for the 214 patients was 28 (range 2–59) months. Most patients had T1 disease (n = 124) and were clinically node negative. Only few patients had high-grade and/or triple-negative disease. The vast majority of patients underwent sentinel node biopsy, and 32 (15%) required re-resection for initially positive margins. Finally, all tumor bed margins were clear. Nine (4.2%) and 48 (22.4%) patients underwent neoadjuvant and adjuvant chemotherapy, respectively. WBI was predominantly performed as conventionally fractionated WBI (n = 187, 87.4%), and the median time from BCS to WBI was 54.5 days. IORT was delivered with a single dose of 20 Gy. The median WBI dose was 50 Gy (range 29.4–50.4 Gy). No patients experienced grade 4 events; acute grade 3 toxicities were limited to 17 (8%) cases of radiation dermatitis. Postoperative toxicities were mild. After WBI only one case of late grade ≥ 2 events was reported. There were two recurrences in the tumor bed and one contralateral breast event. Conclusion This investigation provides additional preliminary data supporting the using of IORT in the boost setting and corroborates the existing literature. These encouraging results should be prospectively validated by the eventual publication of randomized studies such as TARGIT‑B.

Feasibility of Intraoperative Radiotherapy Tumor Bed Boost in Patients with Breast Cancer after Neoadjuvant Chemotherapy

“…Nevertheless, the rate of seroma in the present study (42.1%) was relatively high compared to that of previous reports (3.8%–25.5%). 16 17 18 19 20 There have also been various reports on the effect of IORT on seroma formation. Kraus-Tiefenbacher, et al 21 analyzed the rate of seroma in patients treated with BCS+IORT vs. BCS-only and the rate of seroma was not different (IORT 23%; No-IORT 23%; p =0.933) between the two groups.…”

Major complications after intraoperative radiotherapy with low-energy x-rays in early breast cancer

“…In a retrospective analysis of patients who received IORT as a tumor bed boost by Stoian et al., only grade 1 toxicities were observed postoperatively. The most frequent event was seroma/hematoma of the breast in 10.3% of the patients; all other toxicities such as dermatitis, wound infection, wound dehiscence, or seroma/hematoma of the axilla each occurred in under 2% of the patients [ 24 ]. A study including 93 patients by Gülcelik et al.…”

A single-institution retrospective analysis of intraoperative radiation boost during breast-conservation treatment for breast cancer

“…A recent German study at the University of Freiburg Medical Center, Stoian et al ( 2021 ) investigated the use of IORT to deliver a boost for the tumor bed after BCs in 214 patients with a median follow-up for the 28 (range 2–59) months. There were no grade 4 events, and the only acute grade 3 toxicities were 17 (8%) incidences of radiation dermatitis.…”