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

Lin He,Hao Chang,Yuhong Qi,Qiuju Shao,Dongjie He,Canliang Yuan,Qiming Wang,Jiejing Zhou,Gaiyan Li

doi:10.3389/fonc.2021.759903

Abstract

BackgroundIntraoperative 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 MethodsWe 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.ResultsA 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.ConclusionsDespite 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.

Highlights

Female breast cancer has surpassed lung cancer to become the most common diagnostic cancer in 2020; among women, breast cancer ranks first for the incidence of new diagnostic cancer and cancer-related mortality worldwide, with an estimated 2.254 million new cases (24.5%) and 0.682 million new deaths (15.5%) [1]
The remaining 1,248 citations were evaluated by title and abstract screening, and 1,422 of them were removed; fundamental characteristics of the abstracts were judged with respect to the inclusion and exclusion criteria, and 73 full-length articles were chosen
After full-text scrutinization, 35 of them were further omitted for the following reasons: [1] no provision of the 5-year outcomes in 15 potential articles for calculating the weighted average proportion; [2] no application of a 10–16 Gy boost to the patient in 13 potential studies for calculating the weighted average proportion in the whole-breast irradiation (WBI) cohort; [4] no usage of a single dose of 21 Gy in five potential studies for calculating the weighted average proportion in the Intraoperative radiotherapy (IORT) cohort; and [5] 2 articles with other reasons

Summary

Introduction

Female breast cancer has surpassed lung cancer to become the most common diagnostic cancer in 2020; among women, breast cancer ranks first for the incidence of new diagnostic cancer and cancer-related mortality worldwide, with an estimated 2.254 million new cases (24.5%) and 0.682 million new deaths (15.5%) [1]. Several randomized controlled trials (RCTs) [2,3,4,5,6] and a meta-analysis of the Early Breast Cancer Trialists’ Collaborative Group (EBCTCG) [7] revealed the equivalent overall survival (OS) of early breast cancer patients treated with breast-conserving surgery followed by whole-breast irradiation (WBI) and those undergoing mastectomy. Another meta-analysis of the EBCTCG found that WBI significantly reduced the long-term risk of any first recurrence (i.e., local–regional relapse or distant metastasis) and long-term mortality of early breast cancer patients [8]. 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

Methods

Results

Discussion

Conclusion