Use of electronic brachytherapy to deliver postsurgical adjuvant radiation therapy for endometrial cancer: a retrospective multicenter study

William C Dooley¹, John P Thropay², Gary J Schreiber³, Mohamed Y Puthawala⁴, Steven C Lane⁵, James C Wurzer⁶, Charles E Stewart⁷, Gordon L Grado⁸, Harish G Ahuja⁹, Gary M Proulx^10
1University of Oklahoma Health Sciences Center, Oklahoma City, OK; ²Beverly Oncology and Imaging Center, Montebello, CA; ³Swedish Covenant Medical Center, Chicago, IL; ⁴Rhode Island Hospital, Providence, RI; ⁵Signature Healthcare Brockton Hospital, Brockton, MA; ⁶AtlantiCare Regional Medical Center, Egg Harbor Township, NJ; ⁷St Francis Medical Center, Tulsa, OK; ⁸Southwest Oncology Centers, Scottsdale, AZ; ⁹Aspirus Regional Medical Center, Wausau, WI; ¹⁰Exeter Hospital, Exeter, NH, USA

Background: This retrospective, multicenter study evaluated the feasibility and safety of high-dose rate electronic brachytherapy (EBT) as a postsurgical adjuvant radiation therapy for endometrial cancer.
Methods: Medical records were reviewed from 41 patients (age 40–89 years) with endometrial cancer (Federation of International Gynecology and Obstetrics stages IA–IIIC) treated at nine centers between April 2008 and October 2009. Treatment included intracavitary vaginal EBT alone (n = l6) at doses of 18.0–24.0 Gy in 3–4 fractions and EBT in combination with external beam radiation therapy (EBRT, n = 25) at a total radiation dose range of 40.0–80.4 Gy. Doses were prescribed to a depth of 5 mm from the applicator surface and to the upper third (n = 15) and the upper half (n = 26) of the vagina.
Results: Median follow-up was 3.8 (range 0.5–12.0) months. All 41 patients received the intended dose of radiation as prescribed. Adverse events occurred in 13 of 41 patients and were mild to moderate (Grade 1–2), consisting primarily of vaginal mucositis, rectal mucosal irritation and discomfort, and temporary dysuria and diarrhea. There were no Grade 3 adverse events in the EBT-only treatment group. One patient, who was being treated with the combination of EBT and EBRT for recurrent endometrial cancer, had a Grade 3 adverse event. No recurrences have been reported to date.
Conclusion: Electronic brachytherapy provides a feasible treatment option for postoperative adjuvant vaginal brachytherapy as sole radiation therapy and in combination with EBRT for primary endometrial cancer. Early and late toxicities were mild to moderate.

Keywords: endometrial cancer, electronic brachytherapy, radiation therapy