The incidence of isolated paraaortic nodal metastasis in surgically staged endometrial cancer patients with negative pelvic lymph nodes.

OBJECTIVE: To describe the incidence of isolated paraaortic nodal metastasis in surgically staged endometrial cancer patients with negative pelvic lymph nodes.
METHODS: Using a prospectively maintained database we identified all cases of endometrial cancer that had both pelvic and aortic nodal dissection and determined the rate of isolated paraaortic nodal metastasis in the setting of negative pelvic nodes. For this report a satisfactory pelvic node dissection meant the identification of 8 or more pelvic nodes on final pathology.
RESULTS: 1942 endometrial cancer patients were surgically treated at our institution from 1/93 to 1/08. 847 had both pelvic and paraaortic nodes removed during surgery and identified by pathology. 734 had negative pelvic nodes with at least one paraaortic node identified. Only 12 (1.6%) had positive paraaortic nodes with negative pelvic nodes. Seven (1%) of 640 cases with 8 or more negative pelvic nodes had positive paraaortic nodes. Final grade for these cases included: G1 (2), G2 (2), G3 (1), papillary serous (1), and undifferentiated (1). Of the 570 cases with a final diagnosis of grade 1 endometrial cancer, 187 had both pelvic and aortic node dissection during the same operation, and 2/187 (1%) had a positive paraaortic node with negative pelvic nodes.
CONCLUSIONS: Isolated paraaortic nodal metastasis in the setting of negative pelvic nodes occurs in approximately 1% of surgically staged endometrial cancer cases. This low rate seems consistent for low- and high-grade lesions. Future studies looking at the incidence of isolated paraaortic nodal metastasis in the setting of negative sentinel pelvic nodes are warranted.