Intra-Operative Electron Radiation Therapy (IOERT) Anticipated Boost in Breast Cancer Treatment: An Italian Multicenter Experience.

In breast cancer, the use of a boost to the tumor bed can improve local control. The aim of this research is to evaluate the safety and efficacy of the boost with intra-operative electron radiotherapy (IOERT) in patients with early-stage breast cancer undergoing conservative surgery and postoperative whole breast irradiation (WBI). The present retrospective multicenter large data were collected between January 2011 and March 2018 in 8 Italian Radiation Oncology Departments. Acute and late toxicity, objective (obj) and subjective (subj) cosmetic outcomes, in-field local control (LC), out-field LC, disease-free survival (DFS) and overall survival (OS) were evaluated. Overall, 797 patients were enrolled. IOERT-boost was performed in all patients during surgery, followed by WBI. Acute toxicity (≥G2) occurred in 179 patients (22.46%); one patient developed surgical wound infection (G3). No patients reported late toxicity ≥ G2. Obj-cosmetic result was excellent in 45%, good in 35%, fair in 20% and poor in 0% of cases. Subj-cosmetic result was excellent in 10%, good in 20%, fair in 69% and poor in 0.3% of cases. Median follow-up was 57 months (range 12-109 months). At 5 years, in-field LC was 99.2% (95% CI: 98-99.7); out-field LC 98.9% (95% CI: 97.4-99.6); DFS 96.2% (95% CI: 94.2-97.6); OS 98.6% (95% CI: 97.2-99.3). In conclusion, IOERT-boost appears to be safe, providing excellent local control for early-stage breast cancer. The safety and long-term efficacy should encourage use of this treatment, with the potential to reduce local recurrence.

Toxicity and cosmetic outcome after hypofractionated whole breast irradiation and boost-IOERT in early stage breast cancer (HIOB): First results of a prospective multicenter trial (NCT01343459).

BACKGROUND AND PURPOSE: To assess the role of intraoperative radiation with electrons (IOERT) as tumor bed boost followed by hypofractionated whole breast irradiation (HWBI) after breast conserving surgery (BCS) of patients with low to intermediate risk breast cancer focusing on acute/late toxicity and cosmetic outcome. MATERIAL AND METHODS: In 2011, a prospective multicenter trial (NCT01343459) was started. Treatment consisted of BCS, IOERT (11.1 Gy) and HWBI (40.5 Gy in 15 fractions). In a single-arm design, 5-year IBR-rates are benchmarked by a sequential ratio test (SQRT) against best published evidences in 3 age groups (35-40 y, 41-50 y, >50 y). Acute/late toxicity and cosmesis were evaluated by validated scorings systems. RESULTS: Of 627 eligible patients, 44 were excluded, leaving 583 to analyze. After a median follow-up (FUP) of 45 months (range 0-74), for acute effects CTCAE-score 0/1 was noted in 91% (end of HWBI) and 92% (4 weeks later), respectively. Late toxicity Grading 0/1 (mean values, ranges) by LENT-SOMA criteria were observed in 92.7% (89-97.3) at 4/5 months, rising to 96.5% (91-100) at 6 years post HWBI. Baseline cosmesis after wound healing prior to HWBI was scored as excellent/good in 86% of cases by subjective (patient) and in 74% by objective (doctor) assessment with no impairment thereafter. CONCLUSIONS: Acute and late treatment tolerance of a combined Boost-IOERT/HWBI regimen is excellent in short/mid-term assessment. Postoperative cosmetic appearance is not impaired after 3 years FUP.

Local Failure After Accelerated Partial Breast Irradiation with Intraoperative Radiotherapy with Electrons: An Insight into Management and Outcome from an Italian Multicentric Study.

BACKGROUND: The aim of this work is to evaluate pattern of care and clinical outcome in a large series of patients with in-breast recurrence (IBR), after quadrantectomy and intraoperative radiation therapy with electrons (IOERT) as partial breast irradiation. PATIENTS AND METHODS: Patients with IBR after IOERT, treated with salvage surgery ± adjuvant reirradiation (re-RT), were selected from a multiinstitution database. Disease-free survival (DFS), overall survival (OS), cumulative incidence of second IBR, and distant metastases (DM) were estimated. RESULTS: A total of 224/267 patients from seven institutions were included. Primary tumors received 21 Gy. Median time to first IBR was 4.3 years (range 2.6-6.1 years). Salvage mastectomy and repeat quadrantectomy were performed in 135 (60.3%) and 89 (39.7%) patients, followed by adjuvant re-RT in 21/135 (15.5%) and 63/89 (70.8%), respectively. Median follow-up after salvage treatment was 4.1 years. Overall, 5- and 8-year outcomes were as follows: cumulative incidence of second IBR: 8.4% and 14.8%; cumulative incidence of DM: 17.1% and 22.5%; DFS: 67.4% and 52.5%; OS: 89.3% and 74.7%. The risk of second IBR was similar in the salvage mastectomy and repeat quadrantectomy + RT groups [hazard ratio (HR) 1.41, p = 0.566], while salvage mastectomy patients had greater risk of DM (HR 3.15, p = 0.019), as well as poorer DFS (HR 2.13, p = 0.016) and a trend towards worse OS (HR 3.27, p = 0.059). Patients who underwent repeat quadrantectomy alone had worse outcomes (second IBR, HR 5.63, p = 0.006; DFS, HR 3.21, p = 0.003; OS, HR 4.38, p = 0.044) than those adding re-RT. CONCLUSIONS: Repeat quadrantectomy + RT represents an effective salvage approach and achieved local control comparable to that of salvage mastectomy.