Long-term results of 1-week intravaginal high-dose-rate brachytherapy alone for endometrial cancer

Abstract

Objective: To compare the biologic equivalence in terms of local control and toxicity of a short course of high-dose-rate intravaginal brachytherapy alone (IVBa) delivered over five consecutive days (25 Gy/5 Rx/5 days) to other more protracted classical schemes 21 Gy/3 Rx/14-28 days (Postoperative Radiation Therapy in Endometrial Carcinoma [PORTEC]-2/Memorial Sloan-Kettering Cancer Center).

Methods and materials: From February 2001 to May 2008, 122 patients with International Federation of Gynecology and Obstetrics Stage IaG3-IIIaG2 endometrial adenocarcinoma were treated with total abdominal hysterectomy and bilateral salpingo-oophorectomy followed by postoperative IVBa. Seventy-seven patients (63.1%) underwent surgical staging. Total IVBa dose was 25Gy in five consecutive daily fractions prescribed at 0.5-cm depth.

Results: After a median followup of 4.1 years, the rates of Radiation Therapy Oncology Group Grades 1, 2, and ≥3 complications were 12.9%, 3.4%, and 0.8%, respectively. Five patients (4.1%) presented locoregional failures: two isolated nodal pelvic failures, one vaginal pelvic relapse (intra-abdominal lymph node metastases), one vaginal distant failure, and one combined locoregional and distant failure. The 8.5-year actuarial vaginal control rate was 97.5%, and the pelvic control rate was 94.3%. Six other patients developed distant metastases alone. The 8.5-year actuarial overall and disease-free survival rates were 90.3% and 87.2%, respectively. Univariate analysis revealed that histologic grade, deep myometrial invasion, advanced age, and categorization as high intermediate-risk patient according to the PORTEC-2 and the Gynecologic Oncology Group (GOG)-99 stratifications were statistically significant prognostic factors. After multivariate analysis, histologic grade (p=0.001) and high intermediate risk according to GOG-99 (p=0.004) and PORTEC-2 (p=0.001) remained significant.

Conclusions: The proposed scheme reproduces the excellent results obtained with more protracted schemes and has the added advantage of shortened overall treatment time.