Use of Nodal Staging Score in Evaluating the Accuracy of Pathologic Nodal Status in Node-Negative Ampullary Carcinoma.

BACKGROUND

The minimum number of lymph nodes (LNs) that should be resected for accurate nodal staging in patients with ampullary carcinoma (AC) remains controversial. This study aimed to establish a nodal staging score (NSS) to evaluate whether a pathological node-negative AC patient is indeed free of a nodal disease.

METHODS

A total of 2539 AC patients with stages I-III were retrieved from the Surveillance, Epidemiology and End Result database (design cohort [DC], n = 2382) and First Affiliated Hospital of Sun Yat-sen University (validation cohort [VC], n = 157). NSS was developed to represent the probability that a node-negative patient was correctly staged as a function of the number of examined LNs (ELNs) and pathologic T stage with a beta-binomial model. Its prognostic value in node-negative patients was assessed by survival analysis.

RESULTS

The probability of missing a metastatic LN decreased as the number of the ELNs increased. NSS was escalated as the number of ELNs increased. For patients with early-stage (T1-T2) and late-stage (T3-T4) tumors, examining 7 and 33 lymph nodes could ensure an NSS of 80.0%, respectively. Multivariate analysis showed that higher NSS was an independent favorable prognostic factor for overall survival in node-negative patients with AC (DC, p < 0.001; VC, p = 0.001).

CONCLUSIONS

NSS model could be used to evaluate the accuracy of nodal staging and predict the prognosis of node-negative AC patients. It could assist in making clinical strategies in node-negative AC patients.