Intraoperative radiotherapy in early breast cancer: observational comparison with whole breast radiotherapy

Application of Intraoperative Radiotherapy in Early-Stage Breast Cancer Patients in a Clinical Setting

Background: Intraoperative radiation therapy (IORT) has gained popularity in recent years as an alternative to external beam whole breast radiation therapy (WBRT) for early-stage breast cancer. Here, we report 43-month recurrence and survival outcomes in a multiethnic cohort treated with IORT in a clinical context. Method: Two hundred and eleven patients with low-risk features were treated with IORT for early-stage breast cancer from 2014 to 2021. Selection criteria were based on Group Europeen de Curietherapie-European Society for Therapeutic Radiology and Oncology (GEC-ESTRO) guidelines: preferably unifocal intraductal carcinoma (IDC), aged > 50, tumor size ≤ 2.0 cm, and without lymph node involvement. All patients received 20 Gy of radiation dose during the lumpectomy. Information on patient and tumor characteristics was collected. Results: The mean age of this cohort was 67.5 years; 95.2% of patients are Jewish, and the rest are Bedouins (4.7%). Most tumors were intraductal carcinoma (97.2%) and stage 1 (94.8%). The mean follow-up time was 43.4 months. Bedouins had larger tumor sizes (mean 1.21 vs. 1.13 cm) and were younger at diagnosis than Jewish patients (mean 65.4 vs. 67.6 years), although the differences are not significant. The overall recurrence rate was 1.4%. One case of local recurrence (0.5%) and two cases of metastasis (0.9%) were observed during the study period. One patient died from metastasis. Conclusion: Our findings suggest that IORT in selected low-risk patients can achieve an excellent prognosis with low rates of recurrence and metastasis.

Comparison of the Oncological Efficacy Between Intraoperative Radiotherapy With Whole-Breast Irradiation for Early Breast Cancer: A Meta-Analysis

Background

Intraoperative radiotherapy (IORT) and whole-breast irradiation (WBI) are both effective radiotherapeutic interventions for early breast cancer patients undergoing breast-conserving surgery; however, an issue on whether which one can entail the better prognosis is still controversial. Our study aimed to investigate the 5-year oncological efficacy of the IORT cohort and the WBI cohort, respectively, and compare the oncological efficacy between the cohorts.

Materials and Methods

We conducted a computerized retrieval to identify English published articles between 2000 and 2021 in the PubMed, the Web of Science, the Cochrane Library, and APA PsycInfo databases. Screening, data extraction, and quality assessment were performed in duplicate.

Results

A total of 38 studies were eligible, with 30,225 analyzed participants. A non-comparative binary meta-analysis was performed to calculate the weighted average 5-year local recurrence-free survival (LRFS), distant metastasis-free survival (DMFS), and overall survival (OS) in the two cohorts, respectively. The LRFS, DMFS, and OS (without restriction on the 5-year outcomes) between the two cohorts were further investigated by a comparative binary meta-analysis. The weighted average 5-year LRFS, DMFS, and OS in the IORT cohort were 96.3, 96.6, and 94.1%, respectively, and in the WBI cohort were 98.0, 94.9, and 94.9%, respectively. Our pooled results indicated that the LRFS in the IORT cohort was significantly lower than that in the WBI cohort (pooled odds ratio [OR] = 2.36; 95% confidential interval [CI], 1.66–3.36). Nevertheless, the comparisons of DMFS (pooled OR = 1.00; 95% CI, 0.76–1.31), and OS (pooled OR = 0.95; 95% CI, 0.79–1.14) between the IORT cohort with the WBI cohort were both not statistically significant.

Conclusions

Despite the drastically high 5-year oncological efficacy in both cohorts, the LRFS in the IORT cohort is significantly poorer than that in the WBI cohort, and DMFS and OS do not differ between cohorts.

Intraoperative Radiotherapy with Balloon-Based Electronic Brachytherapy System-A Systematic Review and First Bulgarian Experience in Breast Cancer Patients

(1) Background: We aimed to analyze currently available studies with intraoperative radiotherapy (IORT) as a choice of treatment where the Xoft Axxent^® electronic brachytherapy (eBx) system was used as a single-dose irradiation and an exclusive radiotherapy approach at the time of surgery in patients with early breast cancer (EBC). We also compared the results of the systematic review to the Bulgarian experience. (2) Methods and Materials: We performed a systematic review of the studies published before February 2021, which investigate the application of a single-fraction 20 Gy radiation treatment, delivered at the time of lumpectomy in EBC patients with the Xoft Axxent^® eBx System. A systematic search in PubMed, Scopus, and ScienceDirect was performed. The results are reported following the PRISMA guidelines. The criteria on patients’ selection for IORT (the additional need for EBRT), cosmetic outcomes, and recurrence rate from the eligible studies are compared to the treatment results in Bulgarian patients. (3) Results: We searched through 1032 results to find 17 eligible studies. There are no published outcomes from randomized trials. When reported, the cosmetic outcomes in most of the studies are defined as excellent. The observed recurrence rate is low (1–5.8%). Still, the number of patients additionally referred to postoperative external breast radiotherapy (EBRT) is up to 31%. Amongst the 20 patients treated in Bulgaria, the cosmetic outcomes are also evaluated as excellent, five of which (25%) are referred for EBRT. Within median follow-up of 39 months, there was one local and one distal recurrence. (4) Conclusions: Current evidence demonstrates the Xoft Axxent^® eBx system as a safe and feasible technique for IORT delivery in EBC patients. There are no randomized controlled trials conducted at this time point to prove its long-term effectiveness. Better patient selection and a reimbursement strategy have to be proposed to extend the application of this technique in Bulgaria.