Nodal staging score: A tool to quantify the number of lymph nodes for examination and predict survival in IB–IIA cervical cancer

Abstract

Background

According to current official guidelines, there is no generally recommended minimum number of lymph nodes examined during surgery for cervical cancer. However, patients with few nodes removed are still common, and the prevalence of nodal invasion may be underestimated because of false-negative findings. In this article, we introduced a statistical tool called the Nodal Staging Score (NSS), which predicts the minimum number of examined lymph nodes to confidently ensure a node-negative status preoperatively.

Methods

Using the beta-binomial model, we analyzed lymph node invasion data for 8789 patients with cervical cancer from the Surveillance, Epidemiology, and End Results database. This analysis quantified the number of lymph nodes that require assessment across various early International Federation of Gynecology and Obstetrics (FIGO) stages. We also performed univariate and multivariate Cox regression analyses to explore the prognostic significance of NSS.

Results

With an increased number of examined lymph nodes, the probability of missing nodal disease decreased and varied among different FIGO stages. For stages IB1–IIA, the examination of 6, 21, and 33 lymph nodes, respectively, was required to reduce the probability of missing positive nodes (i.e., 1−NSS) to less than 10%. The clinical significance of NSS was verified with prognostic information. Compared with NSS <0.90, NSS ≥0.90 was significantly associated with better overall survival for node-negative patients.

Conclusion

The NSS is an auxiliary tool that not only enhances the precision of FIGO staging but also provides a statistical basis for postoperative evaluation to inform further clinical decision-making.