Risk-scoring system for the individualized prediction of lymphatic dissemination in patients with endometrioid endometrial cancer.

OBJECTIVE: To develop a risk-scoring system (RSS) for the prediction of lymphatic dissemination after hysterectomy in endometrioid endometrial carcinoma (EC).
METHODS: Patients who underwent surgery from 1/1/1999-12/31/2008 were evaluated. Patients with non-endometrioid histology, stage IV with macroscopic extrauterine disease, or receiving adjuvant therapy (excluding brachytherapy) without pelvic and/or paraaortic (P/PA) lymphadenectomy (LND) were excluded. Lymph node dissemination was defined as nodal metastasis when P/PA LND was performed or P/PA lymph node recurrence after negative LND or when LND was not performed. Logistic regression analysis was used to identify predictors for lymphatic dissemination and develop a RSS and nomogram. The RSS was assessed for calibration and verified for discrimination.
RESULTS: Overall, 883 patients were assessed of which 521 (59.0%) underwent P/PA LND and 57 (10.9%) had positive lymph nodes. Of patients who did not undergo P/PA LND (N=362) or had negative nodes (N=464), 10 (1.2%) patients had P/PA lymph node recurrence. Myometrial invasion, tumor diameter (TD), FIGO grade, cervical stromal invasion and lymphovascular space invasion were significant on univariable analysis. All preceding variables were included in a multivariable logistic model. A parsimonious model and an alternative full model not including TD were considered. The full model with TD (illustrated in nomogram) had the highest predictive ability (concordance index 0.88).
CONCLUSION: Our RSS allows accurate quantification of the probability of lymphatic dissemination and can be used as an adjunct to clinical decision-making after hysterectomy in the absence of staging. TD is an important component of the RSS and should be routinely assessed.