The significance of surgical staging in intermediate-risk endometrial cancer.

OBJECTIVE: The objective was to evaluate rates of nodal disease in endometrial cancer within risk groups based on uterine factors, and to estimate the rate of potential undertreatment and impact on survival if nodal status was unknown. METHODS: This was a population-based retrospective cohort study of endometrioid-type endometrial cancer in British Columbia from 2005 to 2009. All women with a preoperative grade 2/3 cancer underwent hysterectomy, bilateral salpingo-oophorectomy (HBSO) and lymphadenectomy, and those with intermediate- or high-risk disease based on uterine factors after HBSO alone underwent secondary lymphadenectomy. We compared rates of node-positivity and potential undertreatment in each group if nodal status had been unknown (chi-square test), and estimated the survival benefit from lymphadenectomy. RESULTS: There were 222 women who underwent primary or secondary lymphadenectomy. Median age was 65 (range 38-86) and median number of lymph nodes was 10 (range 2-39). Of the 66 women with intermediate-risk disease (grade 1 or 2 tumor, deep myometrial invasion), 6 had nodal disease (9.1%) and received adjuvant chemotherapy. They remain disease-free after 24 months (range 8-55). They would not have qualified for chemotherapy based on uterine factors alone, and would have been undertreated compared to other risk groups (chi-square p=0.071). A 1% survival benefit was estimated from lymphadenectomy. CONCLUSION: Women with a grade 1 or 2 tumor and deep myometrial invasion have a 9% risk of nodal disease. Lymphadenectomy is significant for this subgroup as they would have been undertreated based on uterine risk factors alone, although the survival benefit is limited.