Predicting Lymph Node Metastasis of Endometrial Cancer

Researchers in France have developed a nomogram with high concordance probability that is based on pathological hysterectomy characteristics to predict lymph node metastasis in patients with endometrial cancer, according to a new study.¹ 

Currently, there are no established indications for lymph node dissection in the surgical treatment of patients with endometrial cancer. There is also disagreement about whether lymphadenectomy is beneficial to patients with endometrial cancer. According to the study authors, some physicians believe that complete lymphadenectomy may improve survival outcomes, but others think that the procedure offers no overall or recurrent-free survival benefit in patients with early-stage disease.¹

Certain clinical and pathological variables, specifically age at diagnosis, race, tumor grade, histological subtype, and primary site of invasion, are associated with risk of lymph node metastasis. Alone, these variables have no predictive value for determining which patients would not benefit from a lymphadenectomy. The study authors determined that when used together in a multivariate model, these 5 variables may predict lymph node status in patients with endometrial cancer. An analysis of their nomogram, which could be used when patients have had a hysterectomy without lymphadenectomy, showed promising results.

First, the authors built a logistic regression model using a training set of 18,294 patients. To test the association between metastatic lymph node risk and clinicopathological characteristics, the authors used univariate and multivariate logistic regression analyses. Internal validation was performed with 200 bootstrap resamples. External validation was tested on 434 patients identified from a single database holding patient information from 4 institutions. The nomogram was validated using independent, external, and multicenter data sets, and high concordance probability was demonstrated.

Of the 18,294 patients in the training cohort, 1443 (7.89%) had metastases to the lymph nodes. In the validation set, 57 (13.13%) of 434 patients had lymph node metastases. Overall, the nomogram had good discrimination with an area under the receiver operating characteristic curve of 0.80 in the training set and 0.79 in the validation set. No difference was observed between predicted probabilities and the actual rate of lymph node metastases. This difference never exceeded 9% except for patients in the tenth decile group, in which the difference was 45%. The study authors reported that the predicted and observed probabilities of LN metastasis were 31% and 76%, respectively.

Pertinent Points:
- This 5-variable nomogram has high concordance probability for predicting risk for lymph node metastasis after hysterectomy for endometrial cancer.
- In clinical practice, this nomogram provides individualized information that may help guide treatment decision making and improve patient counseling.
- The nomogram can identify patients who are at risk for lymph node metastasis, which can aid in patient selection for clinical trials evaluating adjuvant treatment strategies.

References:

1. Bendifallah S, Genin AS, Naoura I, et al. A nomogram for predicting lymph node metastasis of presumed stage I and II endometrial cancer. Am J Obstet Gynecol. 2012;207:197.e1-8.