Martin, Jan

5004 Background: Since 1999, patients with low-risk endometrial cancer (EC) as defined by the Mayo criteria have preferably not undergone lymphadenectomy (LND) at our institution. We assess survival, sites of recurrence, morbidity, and cost per up-staged case in this low-risk cohort. Methods: Consecutive patients with Mayo-defined low-risk EC managed without (non-LND) and with LND were compared. Cause-specific survival (CSS) was estimated using the Kaplan-Meier method and compared using the log-rank test. 30-day cost analyses were equated to 2010 Medicare dollars. Results: Among 1,393 consecutive surgically managed EC cases, 385 (27.6%) met the Mayo low-risk criteria, accounting for 34.1% of type I EC. The 5-year CSS of the low-risk cases was 98.6 %. There were 80 LND cases (median # nodes, 29) and 305 non-LND cases. Complications within 30 days occurred in 37.5% and 19.3% of LND and non-LND cases, respectively (P<0.001). Nodal metastasis was identified in a single LND case (1.3%). There were 11 recurrences, 6 of which were vaginal. Not a single recurrence was detected in the pelvic or paraaortic nodal areas in these 385 patients, with a median follow-up of 5.4 years. The estimated prevalence (combining surgery and surveillance) of lymph node metastasis was 0.3%. The 5-year CSS in LND and non-LND cases was 97.3% and 99.0%, respectively (P=0.32). Patients were more than seven times as likely to die of co-morbidities than from EC. The 30-day median cost of care was $15,678 for LND cases compared to $11,028 for non-LND cases (P<0.001). The estimated cost per up-staged low-risk case was $439,990 if performed via endoscopy and $327,866 via laparotomy. If the 305 non-LND cases had been subjected to LND, an estimated additional $1,418,189 would have been expended. Conclusions: For patients with low-risk EC as defined by the Mayo criteria, lymphadenectomy dramatically increases morbidity and 30-day cost of care without discernible short- or long-term benefits: CSS was 99% with a 0.3% rate of nodal metastasis. In these low-risk patients, hysterectomy with salpingo-oophorectomy alone is appropriate surgical management and should be standard of care.