Objective: The aim of this study was to identify determinants of lymphatic failure in patients with endometrial cancer after definitive primary treatment.

Methods: We observed 142 relapses in endometrial cancer patients who had primary surgery at our institution during the decade before 1994. We defined lymphatic failure as a relapse occurring on the pelvic sidewall (PSW), para-aortic area (PAA), or other node-bearing area (i.e., groin, axilla, supraclavicular, mediastinal). Mean follow-up was 72.8 months.

Results: We observed 44 instances of lymphatic failure--6 on the PSW only, 16 in the PAA only, 12 concomitantly in the PAA and on the PSW, and 10 confined in other node-bearing areas. By univariate analysis, body mass index > or = 30 kg/m(2), para-aortic lymph node biopsy, cervical stromal invasion (CSI), positive adnexa, myometrial invasion >50%, primary tumor diameter >2 cm, positive peritoneal cytology, positive lymph nodes (pelvic and/or para-aortic), radiotherapy, grade 3 tumor, nonendometrioid histology, and lymph--vascular invasion (LVI) significantly (P < or = 0.05) correlated with lymphatic failure. However, on Cox regression analysis, only LVI (P < 0.01, relative risk [RR] = 4.27), nodal involvement (P = 0.02, RR = 3.43), and CSI (P = 0.049, RR = 2.26) were independent predictors of lymphatic failure. Moreover, lymph node metastases (P = 0.01, RR = 19.82) and CSI (P = 0.050, RR = 3.57) independently predicted failure on the PSW, and only lymph node involvement (P < 0.01, RR = 10.15) predicted relapse in the PAA.

Conclusion: LVI, positive lymph nodes, and CSI were the strongest predictors of lymphatic failure in endometrial cancer (31% of patients with at least one of the above three variables had a failure at 5 years). Patients with none of the above three factors had an extremely low (<1%) risk of lymphatic failure.