Purpose: Postoperative irradiation of endometrial cancer patients decreases the risk of local recurrence but is associated with a number of long-term sequelae. In a proportion of patients, no immediate postoperative radiotherapy is applied and this treatment is introduced only at relapse. The aim of our study was to assess the long-term results of salvage radiotherapy in previously nonirradiated endometrial cancer patients who developed local recurrence, and to evaluate the impact of patient- and treatment-related factors on treatment efficacy.
Methods and materials: We performed a detailed retrospective analysis of 73 endometrial cancer patients given radiotherapy for local recurrence after the initial surgery only. The mean age at diagnosis of the recurrence was 63 years (range, 39-78 years). Median time to recurrence was 11 months (range, 1-19 months). All recurrences were staged with the use of Perez modification of the International Federation of Gynecology and Obstetrics (FIGO) staging system for primary vaginal carcinoma. There were five (7%) Stage I patients, 43 (59%) Stage II patients, and 25 (34%) Stage III patients. Forty-four patients (60%) received both external beam irradiation (EBRT) and endovaginal brachytherapy (BRT), 17 (23%) received only BRT, and 12 (17%) received only EBRT. The mean total physical radiation dose was 75.9 Gy (range, 8-130 Gy), and the mean normalized total dose (NTD) calculated on the base of the linear-quadratic model was 86.6 Gy (range, 8.5-171.9 Gy). Median follow-up for alive patients was 8.8 years (range, 3-21 years). The impact of patient-, tumor-, and therapy-related factors on the treatment outcome was evaluated with the use of uni- and multivariate analyses.
Results: Three- and 5-year overall survival rates were 33% and 25%, respectively. In the univariate analysis, lower stage of recurrent disease (p < 0.0005), combined EBRT and BRT (p = 0.027), higher total radiation dose (p = 0.031), and higher NTD (p = 0.006) were significantly correlated with better survival. In the multivariate analysis, only stage of recurrent disease (p < 0.005) and high total dose (p = 0.047) were independently correlated with better survival. Lower FIGO stage of recurrence (p = 0.023) and higher total dose (p = 0.005) were also independently correlated with longer time to progression, whereas higher radiotherapy dose was the only factor correlated with better local control (p = 0.029).
Conclusions: The efficacy of salvage radiotherapy in endometrial cancer patients with local failure after previous surgery is limited. Factors determining treatment outcome include advancement of the tumor at relapse and radiotherapy dose.