Timing of Postoperative Radiation Therapy for Early-Stage Endometrial Carcinoma: A 20-Year Single-Center Retrospective Cohort Experience in China

Abstract

To investigate the appropriate timing of radiotherapy (RT) after hysterectomy for women with early-stage endometrial carcinoma (EC). Between 1999 and 2020, 1080 patients with I and II endometrial cancer received postoperative RT at our hospital. All patients underwent hysterectomy followed by RT. The optimal cut-off values for the surgery-RT interval (SRI) based on overall survival (OS) were determined using the R software. The disease-free survival (DFS), OS, locoregional recurrence free survival (LRFS), and distant metastasis free survival (DMFS) rates were estimated using the Kaplan-Meier method. Multivariate analyses were performed using Cox proportional hazards regression. Median follow-up time was 52 months. Median SRI were 46 days. The optimal cut-off value for the surgery-RT interval (SRI) based on overall survival (OS) is 40 days. The group initiated RT within 40 days following surgery has higher OS (P = 0.004), higher LRFS (P = 0.002) and higher DMFS (P = 0.039). An SRI of ≤ 40 days was independently associated with higher OS (HR 0.454, 95% CI:0.261-0.788), higher LRFS (HR 0.487, 95% CI:0.304-0.779), and higher DMFS (HR 0.643, 95% CI:0.421-0.982) than SRI of >40 days. However, SRI had no significant effect on DFS. The surgery-RT interval affects the patients' survival endpoints. Based on this analysis, the timing of the initiation of RT after hysterectomy is crucial for patients with early-stage endometrial carcinoma (EC). The postoperative radiation therapy for endometrial cancer should be initiated within 40 days following surgery.