Oncologic Outcomes After Adjuvant Radiotherapy for Stage II Endometrial Carcinoma: A Korean Radiation Oncology Group Study (KROG 14-10)

OBJECTIVE: The aim of this study was to investigate the survival, patterns of failure, and prognostic factors in patients with stage II endometrial carcinoma treated with adjuvant radiotherapy.

METHODS: We reviewed the medical records of patients who underwent total hysterectomy, bilateral salpingo-oophorectomy, and pelvic lymph node dissection followed by adjuvant radiotherapy in 10 participating hospitals of the Korean Radiation Oncology Group. Most patients received adjuvant external beam radiation therapy, with a median dose of 50.4 Gy; approximately 50% of these patients received an additional brachytherapy boost, with a median dose of 18 Gy. Adjuvant chemotherapy was administered to 19 patients.

RESULTS: A total of 122 patients were examined. Over a median follow-up period of 62.7 months (range, 1.9-158.8 months), the 5-year overall survival (OS) and disease-free survival rates were found to be 91.1% and 85.1%, respectively. Recurrence was observed in 14 patients (11.5%), including 3 with local recurrence and 11 with distant metastases as the first site of recurrence. Univariate analysis indicated that lymphovascular invasion was related to an unfavorable OS. An age of 60 years or above, histologic grade 3, and lymphovascular invasion were identified as risk factors for OS. Because there were several risk factors related to OS, we assigned patients to a high-risk group (defined as cases with ≥1 risk factors) and a low-risk group. The 5-year OS rate of the high-risk group was significantly inferior to that of the low-risk group (82.9% vs 100%, P = 0.003).

CONCLUSIONS: The high-risk group had a significantly poorer survival rate than the low-risk group, and distant metastasis was the main pattern of recurrence, thus indicating that further adjuvant chemotherapy should be considered in high-risk patients.