The Prognostic Impact of Time Interval Between Hysterectomy and Initiation of Adjuvant Radiation Treatment in Women With Early-Stage Endometrial Carcinoma

Purpose/Objective(s): Adjuvant radiation therapy (ART) is indicated for women with endometrial carcinoma (EC) who are at high risk for recurrence. However, due to various reasons, some patients do not receive ART in a timely manner. In this study, we evaluated the prognostic impact of the time interval (TI) between hysterectomy and starting date of ART. Materials/Methods: After institutional review board approval, we queried our prospectively-maintained institutional database for women with uterine endometrioid EC of 2009 FIGO stages I-II who received ART without chemotherapy after surgical staging. The patients were classified into two groups, based on whether they received ART ≤8 weeks (group A) or \u3e8 weeks (group B) after hysterectomy. We then compared the two groups with regards to the following survival endpoints: recurrence-free survival (RFS), disease-specific survival (DSS) and overall survival (OS). Univariate and multivariate analyses were also performed. Results: A total of 460 patients were identified. Median follow-up duration was 70.5 months. The median age for the entire cohort was 66.0 years. The cohort consisted of 176 patients with FIGO stage IA (38%), 207 (45%) with stage IB and 77 (17%) with stage II. Group A consisted of 354 (77%) patients, and group B had 106 (23%). The median TIs from hysterectomy to ART were 6 weeks and 10 weeks for groups A and B, respectively. There was no statistically significant difference between the groups in terms of baseline demographic and disease characteristics including age, race, grade, FIGO stage, extent of myometrial invasion, presence of lymphovascular space invasion and radiation treatment modality. A total of 52 patients experienced recurrences. Patients in group A (vs. group B) experienced significantly less recurrences overall (9% vs. 18%; p = 0.01). Rate of vaginal recurrence was significantly lower in group A (9% vs. 42%, p = 0.01). Univariate analysis showed that having RT ≤8 weeks was associated with significantly improved 5-year RFS rate, which was 89% and 80% for groups A and B (p = 0.04), respectively. The rates of 5-year OS (86% vs. 85% for groups A and B, respectively) and 5-year DSS (93% vs. 93% for groups A and B, respectively) were similar. In addition, multivariate analysis showed a statistical trend for improved 5-year RFS when receiving RT ≤8 weeks (p = 0.07). Conclusion: Our study suggests that delaying adjuvant radiation treatment beyond 8 weeks post-hysterectomy is associated with significantly more cancer recurrences for women with early-stage endometrial cancer