Prospective assessment of lymphatic dissemination in endometrial cancer: a paradigm shift in surgical staging

Abstract

Objective: To prospectively assess pelvic and para-aortic lymph node metastases in endometrial cancer with lymphatic dissemination, emphasizing the examination of para-aortic metastases relative to the inferior mesenteric artery (IMA).

Methods: Over 36 months, 422 consecutive patients were managed by predefined surgical guidelines differentiating low-risk patients from patients at risk for dissemination requiring systematic lymphadenectomy. Low risk was defined as grade 1 or 2 endometrioid type with myometrial invasion (MI) < or = 50% and primary tumor diameter (PTD) < or = 2 cm. Pelvic and para-aortic lymph nodes were submitted separately, with nodes identified from all 8 pelvic and 4 para-aortic node-bearing basins. Surgical quality assessments examined median node counts (primary surrogate for quality) and nodes harvested above and below the IMA and excised gonadal veins (secondary surrogates).

Results: Lymphadenectomy was not required in 27% of patients (all low risk) and in 33% (n=112) of endometrioid cases. However, 22 patients (20%) of this latter cohort had lymphadenectomy and all lymph nodes were negative. Sixty-three (22%) of 281 patients undergoing lymphadenectomy had lymph node metastases: both pelvic and para-aortic in 51%, only pelvic in 33%, and isolated to the para-aortic area in 16%. Therefore, 67% of patients with lymphatic dissemination had para-aortic lymph node metastases. Furthermore, 77% of patients with para-aortic node involvement had metastases above the IMA, whereas nodes in the ipsilateral para-aortic area below the IMA and ipsilateral common iliac basin were declared negative in 60% and 71%, respectively. Gonadal veins were excised in 25 patients with para-aortic node metastases; 7 patients (28%) had documented metastatic involvement of gonadal veins or surrounding soft tissue.

Conclusions: The high rate of lymphatic metastasis above the IMA indicates the need for systematic pelvic and para-aortic lymphadenectomy (vs sampling) up to the renal vessels. The latter should include consideration of excision of the gonadal veins. Conversely, lymphadenectomy does not benefit patients with grade 1 and 2 endometrioid lesions with MI < or = 50% and PTD < or = 2 cm.

Fig. 1

Treatment distribution by defined surgical guidelines as detailed in Table 1 for patients with endometrial cancer (EndoCa) managed during the 36-month period between 2004 and 2006. LND indicates lymph node dissection (either pelvic, para-aortic, or both).

Fig. 2

Surgical quality assessments detailed the mean number and 95% confidence intervals (diamonds) and 1 SD (horizontal lines) from group mean of lymph nodes removed per site and surgeon from 2 successive interim analyses. First interim analysis (after 10 months) of the efficiency of harvesting pelvic (a) and para-aortic (b) nodes denoting the mean, 95% confidence interval, and 1 SD per surgeon relative to the group mean. Second interim analysis (after 21 months) to assess quality improvement for pelvic (c) and para-aortic (d) lymphadenectomy performed by each surgeon. LND indicates lymph node dissection.