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.