The relationship between nodal micrometastases and clinical outcome of endometrial cancer is unclear.

We performed a multicenter, retrospective registry-based study of 2392 patients with endometrial cancer with and without nodal micrometastases. The primary outcome measure was disease-free survival.

After exclusions, the final study involved 428 patients: 302 (70.6%) with node-negative endometrial cancer, who did not receive adjuvant treatment, 95 (22.2%) with nodal micrometastases who received adjuvant treatment, and 31 (7.2%) with nodal micrometastases who did not receive adjuvant treatment. The median follow-up was 84.8 months. Without adjuvant therapy the disease-free survival in the cohort of patients with micrometastases was significantly reduced as compared with disease-free survival in the node-negative cohort (p = 0.0001). With adjuvant therapy the median disease-free survival of patients with nodal micrometastases was similar with those of node-negative patients (p = 0.648). The adjusted hazard ratio for disease events among patients with micrometastases and no adjuvant therapy, as compared with node-negative patients, was 2.23 (95% confidence interval [CI] 1.26-3.95). In the cohort with micrometastases the relative risk of events was significantly decreased by adjuvant therapy (HR 0.29, 95%CI 0.13-0.65) even after adjustment for age at diagnosis, myometrial invasion, histological grade and type, and performance status.

Nodal micrometastases are associated with decreased disease-free survival of patients with endometrial cancer. Adjuvant therapy was associated with improved disease-free survival of patients with micrometastases.