Image-guided high-dose-rate intracavitary brachytherapy in the treatment of medically inoperable early-stage endometrioid type endometrial adenocarcinoma.

PURPOSE The purpose of this case series is to describe the treatment and outcomes of a cohort of patients with inoperable early-stage endometrioid endometrial cancer with 3D image-guided high-dose-rate (HDR) intracavitary brachytherapy. MATERIALS AND METHODS A review was performed of patients with early-stage endometrial cancer who underwent primary radiation treatment between 2010 and 2016. Staging and treatment planning were performed CT, pelvic ultrasound, and pelvic MRI. Gross tumor volume (GTV) was defined as the MRI or ultrasound demonstrated endometrial stripe width, with the entire uterine corpus, cervix, and proximal vagina representing the clinical target volume (CTV). Dosimetry calculations were performed in each fraction of HDR brachytherapy. RESULTS Eight patients received external beam radiation therapy followed by intracavitary HDR brachytherapy. Seven patients underwent intracavitary HDR brachytherapy alone. In all patients, mean cumulative dose to 90% (D90) of GTV was 95.99 Gy in equivalent dose in 2 Gy fractions (EQD2, α/β = 10). Mean cumulative D90 EQD2 to CTV was 51.64 Gy. Average follow-up was 29 months. Four patients died from concurrent disease(s) at an average of 2.83 years after completion of treatment. Except for 1 (6.6%) patient who recurred at 9 months following completion of treatment, all patients remained disease-free for the remainder of follow-up. CONCLUSIONS In patients who are poor surgical candidates and have early-stage endometrioid type endometrial carcinoma, image-guided HDR intracavitary brachytherapy carries minimal side effects and a high response rate.