Three-Year Recurrence-Free Survival in Patients With a Very Low Risk of Endometrial Cancer Who Did Not Undergo Lymph Node Dissection (Tree Retro): A Korean Multicenter Study.

OBJECTIVE: Randomized studies have not demonstrated a survival benefit of routine lymph node dissection in early-stage endometrial cancer. Many surgeons nevertheless perform lymph node dissection in all patients with early-stage endometrial cancer. This study aimed to ascertain the survival outcomes of very low-risk endometrial cancer patients (by the Korean Gynecologic Oncology Group [KGOG] criteria) who did not undergo lymph node dissection. MATERIALS AND METHODS: Medical records of 156 consecutive patients who underwent surgical staging without lymph node dissection were collected from 10 institutions. All patients fulfilled the KGOG criteria: (1) endometrioid corpus cancer diagnosed by preoperative endometrial biopsy, (2) serum cancer antigen-125 level ≤35 IU/mL, (3) <50% myometrial invasion with no extension beyond the uterine corpus by magnetic resonance imaging (MRI), and (4) no lymph nodes with a short diameter ≥1.0 cm by MRI or computed tomography. Sampling of <5 nodes was allowed at a surgeon's discretion. We evaluated the 3-year recurrence-free survival (RFS) and 5-year overall survival (OS) using the Kaplan-Meier method. RESULTS: The median patient age was 52 years (range, 24-86 years). The median follow-up was 59 months (range, 0-189 months). The 3-year RFS and 5-year OS were 98.6% (95% confidence interval [CI], 96.8%-100.0%) and 98.6% (95% CI, 96.7%-100.0%), respectively. No disease-related mortality occurred. The final pathology report revealed ≥50% myometrial invasion in 29 patients (18.6%) and extension beyond the uterine corpus in 2 patients (1.3%). One patient (0.6%) was diagnosed with lymph node metastasis after lymph node sampling. Eighteen patients (11.5%) received adjuvant therapy after the final pathologic results indicated high risk. CONCLUSIONS: Very low-risk patients who did not undergo lymph node dissection had acceptable survival outcomes. Omitting lymph node dissection may be reasonable in patients satisfying the KGOG criteria.