Image-guided tandem and cylinder brachytherapy as monotherapy for definitive treatment of inoperable endometrial carcinoma

Abstract

Objectives Management of endometrial cancer consists of surgical staging with adjuvant therapy guided by risk factors, though some women cannot undergo surgery due to comorbidities. We present a series of women treated with definitive high-dose rate image-guided tandem and cylinder brachytherapy (HDR-IGBT) alone. Methods Patients with grade 1–2, clinical stage I endometrial adenocarcinoma, < 50% myometrial invasion, and tumor ≤ 2 cm were reviewed. Definitive treatment consisted of 5–6 fractions HDR-IGBT alone with CT- or MRI-based planning. Local-regional control (LRC) was defined as complete imaging response and/or cessation of vaginal bleeding. Results From 2007 to 2016, 45 patients were treated to a median dose of 37.5 Gy. The median gross tumor volume (GTV) and clinical target volume (CTV) were 5.9 cm3 (range, 0.7–18.7) and 80.9 cm3 (17.2–159.0), respectively. The median cumulative dose to 90% (D90) of the GTV was 132.8 Gy (76.5–295.6) equivalent 2 Gy dose, and the median CTV D90 was 49.7 Gy (34.5–57.2). Median follow-up among living patients was 18.6 months (3.0–64.3). Cessation of vaginal bleeding occurred in 98%. Among those with post-treatment MRI (64%), complete radiographic response was demonstrated in 90%. The 2-year LRC, cancer-specific survival, and overall survival rates were 90%, 86%, and 97%, respectively. No grade 3 + acute or late toxicity was observed. Conclusions HDR-IGBT alone for treatment of early-stage, medically inoperable endometrial cancer is feasible with excellent response rates and clinical results. This approach also allows sparing of critical organs and ensures target coverage, which contributed to the low toxicity rate and high LRC in comparison with 2D point-based series.