Micrometastasis of endometrial cancer to sentinel lymph nodes: Is it an artifact of uterine manipulation?

Objective. To determine if micrometastasis (MM) and isolated tumor cells (ITCs) in sentinel lymph nodes (SLNs) of endometrial cancer patients are artifactual and related to uterine manipulation at the time of diagnosis and surgery. Methods. We reviewed a prospectively maintained database of all patients with endometrial cancer undergoing SLN mapping between 2005 and 2009. MM was defined as a focus of metastatic cancer ranging from 0.2 to 2 mm. ITCs were defined as metastasis measuring <=.2 mm, including the presence of single, noncohesive cytokeratin-positive tumor cells. We reviewed the effect of diagnostic procedure such as dilatation and curettage (D&C) versus biopsy and type of hysterectomy performed on the presence of MM and ITCs in SLNs. Results. In all, 175 patients had successful SLN mapping. Of these, 145 (83%) had negative nodes, 11(6%) had positive nodes, and 19 (11%) met the criteria for MM and ITC. The uterine procedure used to diagnose endometrial cancer, type of hysterectomy, tumor grade, histology, positive pelvic washings, and type of uterine manipulator utilized, did not appear to be associated with MM/ITC. However, the presence of lymphovascular invasion (P<0.001) and the depth of myometrial invasion (P=0.01) were significantly higher in the MM/ITC group. Conclusions. These data demonstrate that the presence of MM and ITCs in SLNs of endometrial cancer patients is not an artifact of uterine manipulation or instrumentation. Rather, it is a real pathologic finding likely associated with lymphovascular invasion and depth of myoinvasion. (C) 2010 Elsevier Inc. All rights reserved.