The outcomes of 27,063 women with unstaged endometrioid uterine cancer.

Background: Over two-thirds of patients with endometrioid uterine cancer in the Surveillance, Epidemiology and End Results program from 1988 to 2001 did not undergo a lymphadenectomy. These patients were compared to those who had a lymphadenectomy.
Methods: Kaplan-Meier methods and Cox proportional hazards regression analyses were employed.
Results: Of 39,396 women (median age: 65 years) with endometrioid uterine cancers, 12,333 (31.3%) underwent surgical staging procedures including lymphadenectomy. The remainder did not receive a lymphadenectomy. The 5-year disease-specific survival (DSS) of stages I-IV women who underwent lymphadenectomy were 95.5%, 90.4%, 73.8%, and 53.3% compared to 96.6%, 82.2%, 63.1%, and 26.9% in those without lymphadenectomy (p>0.05 for stage I; p<0.001 for stages II-IV). In stage I patients, those who did not receive lymphadenectomy had a higher proportion of tumors with grade 1 histology and/or disease limited to the endometrium compared to those who underwent lymphadenectomy (54.8 % vs. 34.7%; p<0.001, grade 1 disease; 26.6% vs. 15.9%; p<0.001, no myometrial invasion). In patients with stage I grade 3 disease, those who underwent lymphadenectomy had a better 5-year DSS than those without lymphadenectomy (90% vs. 85%; p=0.0001); however, no benefit for lymphadenectomy was seen for patients with stage I grade 1 (p=0.26) and grade 2 (p=0.14) disease. On multivariable analysis, younger age, Caucasian race, early-stage disease, low grade histology, and lymphadenectomy were independent prognostic factors for improved disease-specific survival.
Conclusions: Our data suggest that lymphadenectomy is associated with an improved survival in stage I grade 3 and more advanced endometrioid uterine cancers.