Evaluating the feasibility of modern external beam radiotherapy as an alternative approach to brachytherapy in endometrial cancer treatment: A systematic review

Purpose: This systematic review aimed to assess the feasibility, safety, and efficacy of using modern external beam radiotherapy (EBRT) techniques, such as intensity-modulated radiotherapy (IMRT), volumetric modulated arc therapy (VMAT), and stereotactic body radiotherapy (SBRT) as alternative approaches to brachytherapy (BRT) in adjuvant treatment of endometrial cancer (EC). Material and methods: A systematic review was conducted following PRISMA guidelines. The research question was framed using the PICO method, focusing on patients with EC [P] and comparing modern EBRT techniques (IMRT, VMAT, SBRT) [I] vs. BRT [C], to evaluate their feasibility, safety, and effectiveness, particularly in terms of tumor local control (LC) [O]. Both planning and clinical outcomes, including acute toxicity, late side effects, and LC were analyzed with quality assessments performed using the GRADE framework and ROBINS-I tool. Results: Planning studies revealed that while IMRT and VMAT provided comparable or improved target coverage and dose homogeneity compared with BRT, brachytherapy was associated with lower doses to critical organs. Post-operative SBRT and SIB-VMAT studies reported high LC rates (up to 100%) with minimal acute toxicity. However, the overall quality of evidence was low to very low, with significant risks of bias, mainly related to participant selection. Conclusions: This review highlights that, although modern EBRT techniques, such as IMRT and VMAT are feasible alternative approaches to BRT for post-operative vaginal cuff irradiation, the current evidence does not support their superiority over BRT. Brachytherapy remains a highly effective treatment modality with well-established benefits. Future research should focus on more robust comparisons between EBRT and BRT, considering not only local control and toxicity, but also psychological impact and quality of life, especially in low-resource settings, where access to BRT may be limited.