Objective The benefits of adjuvant radiation treatment after hysterectomy have been confirmed in select patients with early-stage endometrial carcinoma. The goal of this study was to evaluate the prognostic impact of the time interval between hysterectomy and starting adjuvant radiation treatment in patients with early-stage endometrial carcinoma.

Methods Our database was searched for women with early-stage endometrioid endometrial cancer who received adjuvant radiation therapy after hysterectomy. The patients were classified into two groups based on the time interval to adjuvant radiation therapy (≤8 weeks or >8 weeks) after hysterectomy. Recurrence-free survival, disease-specific survival, and overall survival were compared between the two groups.

Results Four hundred and sixty patients were identified. Median follow-up was 70.5 months (range 1–360). One hundred and seventy-six patients (38%) were 2009 International Federation of Gynecology and Obstetrics stage IA, 207 (45%) stage IB, and 77 (17%) stage II. Three hundred and fifty-four women (77%) received adjuvant radiation therapy within 8 weeks after hysterectomy. There was no statistically significant difference between the two groups in baseline demographics, disease and treatment characteristics, except for the modality of adjuvant radiation therapy. Patients who received adjuvant radiation therapy within 8 weeks experienced significantly less disease recurrence (9% vs 18%; p=0.01) and particularly less isolated vaginal recurrence (0% vs 6%, p=0.04). Five-year recurrence-free survival was 89% versus 80% (p=0.04), 5-year disease-specific survival was 93% for both groups, and 5-year overall survival was 86% versus 85% for patients who received adjuvant radiation therapy ≤8 and >8 weeks, respectively (p=0.88).

Conclusion Our study suggests that delaying adjuvant radiation therapy beyond 8 weeks after hysterectomy is associated with significantly more cancer recurrences for women with early-stage endometrial carcinoma.