Survival implications of staging lymphadenectomy for non-endometrioid endometrial cancers.

PURPOSE: To determine, in patients with non-endometrioid endometrial carcinoma, 1) survival benefit associated with pelvic lymphadenectomy (LND), 2) survival benefit for para-aortic lymphadenectomy performed in addition to pelvic lymphadenectomy, and 3) association between number of lymph nodes removed and survival.

METHODS: Patients with clinical stage I serous carcinoma, clear cell carcinoma, or carcinosarcoma who underwent hysterectomy from 2010 to 2013 were identified from the National Cancer Database. Hazard ratio (HR) for death was assessed using propensity score-weighted multivariable Cox regression models. Subgroup analyses assessed for differences in risk of death among histologic subtypes.

RESULTS: 7250 patients met study criteria. 930 (13%) did not undergo LND; 2177 (30%) underwent pelvic LND alone; 4143 (57%) underwent pelvic+para-aortic LND. On propensity score-weighted analysis, pelvic LND was associated with decreased risk of death (HR=0.65, 95% CI: 0.59-0.71) compared to no LND. Pelvic+para-aortic LND was associated with decreased risk of death (HR=0.85, 95% CI: 0.79-0.91) compared to pelvic LND for patients with serous carcinoma. Removal of >15 nodes was independently associated with decreased HR for death (HR=0.86, 95% CI: 0.77-0.96); this association persisted when analysis was limited to patients with node-positive disease (HR=0.78, 95% CI: 0.63-0.95).

CONCLUSIONS: LND is associated with survival benefit in patients with non-endometrioid endometrial cancers. Addition of para-aortic LND to pelvic LND may be most beneficial for patients with serous carcinoma. Systematic lymphadenectomy may be associated with survival benefit through detection and microscopic cytoreduction of occult disease.