The product of the number of positive lymph nodes and tumor differentiation grade affects the prognosis of parotid gland carcinoma

An increasing number of composite indicators have been utilized to evaluate the prognosis of tumors. However, there is currently no study investigating the association between the product of the number of positive lymph nodes and tumor differentiation grade (NPLN×TDG) and the prognosis of parotid gland carcinoma (PGC). A retrospective analysis was conducted on the clinical data of patients diagnosed with PGC from 2004 to 2015 in the Surveillance, Epidemiology, and End Results (SEER) database. This study analyzed 3,821 patients with PDC. The X-tile software was utilized to determine the optimal cut-off values for partial continuous variables and change continuous variables into categorical variables. Multivariate COX regression analysis revealed that the independent prognostic factors for PGC were age, sex, tumor differentiation grade, American Joint Committee on Cancer (AJCC) T-stage, AJCC M-stage, tumor size, and NPLN×TDG. The accuracy of the prediction was evaluated using the C-index and calibration curve. Decision curve analysis (DCA) was utilized to compare the nomogram with the AJCC stage system in order to assess its superiority. The predictive model constructed based on variables included in this study demonstrated good predictive performance, providing a valuable reference for clinical decision-making.