Ultrastaging of 'negative' pelvic lymph nodes in patients with low- and intermediate-risk endometrioid endometrial cancer who developed non-vaginal recurrences.

Objective: Evidence on micrometastases and isolated tumor cells as factors associated with non-vaginal recurrence in low- and intermediate-risk endometrial cancer is limited. The goal of our study was to investigate risk factors for non-vaginal recurrence in low- and intermediate-risk endometrial cancer.

Methods: Records of all patients with endometrial cancer surgically managed at the Mayo Clinic before sentinel lymph node implementation (1999-2008) were reviewed. We identified all patients with endometrioid low-risk (International Federation of Gynecology and Obstetrics (FIGO) stage I, grade 1 or 2 with myometrial invasion <50% and negative peritoneal cytology) or intermediate-risk (FIGO stage I, grade 1 or 2 with myometrial invasion ≥50% or grade 3 with myometrial invasion <50% and negative peritoneal cytology) endometrial cancer at definitive pathology after pelvic and para-aortic lymph node assessment. All pelvic lymph nodes of patients with non-vaginal recurrence (any recurrence excluding isolated vaginal cuff recurrences) underwent ultrastaging.

Results: Among 1303 women, we identified 321 patients with low-risk (n=236) or intermediate-risk (n=85) endometrial cancer (median age 65.4 years; 266 (82.9%) stage IA; 55 (17.1%) stage IB). Of the total of 321, 13 patients developed non-vaginal recurrence (Kaplan-Meier rate 4.7% by 60 months; 95% CI 2.1% to 7.2%): 11 hematogenous/peritoneal and two para-aortic and distant lymphatic. Myometrial invasion and lymphovascular space invasion were univariately associated with non-vaginal recurrence. In these patients, the original hematoxylin/eosin slides review confirmed all 646 pelvic and para-aortic removed lymph nodes as negative. The ultrastaging of 463 pelvic lymph nodes did not identify any occult metastases (prevalence 0%; 95% CI 0% to 22.8% considering 13 patients; 95% CI 0% to 0.8% considering 463 pelvic lymph nodes).

Conclusion: There were no occult metastases in pelvic lymph nodes of patients with low- or intermediate-risk endometrial cancer with non-vaginal recurrence. Myometrial invasion and lymphovascular space invasion appear to be associated with non-vaginal recurrence.