Abstract

Adjuvant radiotherapy is an important component of post-operative therapy for patients with early-stage endometrial cancer. In the past decades, many trials have been conducted to determine the optimal adjuvant treatment strategy, pelvic external beam radiotherapy or vaginal brachytherapy. As a result, vaginal brachytherapy became the treatment of choice for patients with early-stage endometrial cancer at high-intermediate risk, based on clinicopathological risk factors. Vaginal brachytherapy maximizes local control and has only mild side effects with limited impact on quality of life, in comparison with pelvic external beam radiotherapy. The most frequently used treatment schedule is the one which was used in the PORTEC-2 trial (21 Gy in three fractions specified at 5 mm depth) and, whenever available, image-guided brachytherapy should be used. However, the most convenient and effective treatment schedule remains to be established. More recently, the discovery and integration of four molecular classes in the risk assessment of endometrial cancer patients has created new opportunities to prevent over- and undertreatment. The 2021 endometrial cancer guideline of the European Society of Gynaecological Oncology (ESGO), European Society for Radiotherapy and Oncology (ESTRO), and the European Society of Pathology (ESP) now proposes an integrated risk stratification, in which both clinicopathologic and molecular factors are combined, to direct adjuvant therapy. This rationale is now investigated in multiple prospective trials. This review provides an overview of the rationale and currently recommended and new strategies for vaginal brachytherapy in patients with stage I and II endometrial cancer.