The prognostic significance of lower uterine segment involvement in surgically staged endometrial cancer patients with negative nodes

OBJECTIVES: Endometrial cancer is the most common female genital malignancy in the United States. Stage is the most important prognostic factor. Other factors include grade, lymph-vascular space invasion (LVI), and myometrial invasion. Tumor location in the lower uterine segment (LUS) may also be important. LUS involvement correlates with nodal involvement, and nodal involvement is an important prognostic indicator. This study investigates the importance of LUS involvement in patients with pathologically negative nodes. METHODS: This was an IRB approved retrospective study. Data were collected for patients diagnosed with endometrial cancer from June 1999 to September 2004. Patients who underwent nodal evaluation with no evidence of nodal disease were eligible for analysis. The primary endpoint was progression-free survival. Secondary endpoints included recurrence rate and overall survival. Analysis was performed with the JMP5.1 statistical program. RESULTS: 285 patients were identified. 85 were excluded because they received postoperative care elsewhere. 3 charts were missing, and 15 pathology reports did not mention LUS. 147 of the remaining 182 subjects had negative nodes and formed the study population. 57% of these subjects had LUS involvement. Follow-up was similar for those with and without LUS involvement at 74 vs. 73 months respectively. PFS was similar at 70 and 63 months in those with and without LUS involvement (p=0.2). Recurrence correlated with LUS involvement on univariate analysis, however, not on multivariate analysis. CONCLUSIONS: In endometrial cancer patients with negative nodes, disease within the lower uterine segment does not imply a worse prognosis. The previously described implications of LUS involvement are likely due to the strong association of LUS disease with lymph node spread.