Establishment of a nomogram prediction model for long diameter 10-15 mm gallbladder polyps with malignant tendency

Surgical indications for the treatment of gallbladder polyps are controversial. Evaluation of gallbladder polyps with malignant tendency and indications for cholecystectomy in patients with long diameter polyps of 10 to 15 mm require further analysis and discussion. In this study, our objective was to re-evaluate indications for the surgical resection of gallbladder polyps and construct a nomogram model for the prediction of gallbladder polyps with malignant tendency.

Clinicopathologic data of 2,272 patients who had undergone cholecystectomy for gallbladder polyps were collected from 11 medical centers in China. Risk factor analyses and nomogram prediction model for gallbladder polyps with malignant tendency were conducted.

Excluding 311 patients with cholelithiasis and 488 patients with long diameter polyps ≤5 and >15 mm, factors that differed significantly among patients with gallbladder polyps having a long diameter of 6 to 9 mm (885 cases) and 10 to 15 mm (588 cases) were polyp detection time, CEA and CA19-9 levels, number of polyps, fundus, echogenicity, gallbladder wall thickness and postoperative pathologic features (P < .05). Among 588 patients with gallbladder polyps with a long diameter of 10 of 15 mm, multivariate analysis indicated the following independent risk factors of gallbladder polyps with malignant tendency: single polyps (OR = 0.286/P < .001), polyps with broad base (OR = 2.644/P = .001), polyps with medium/low echogenicity (OR = 2.387/P = .003), and polyps with short diameter of 7 to 9 or 10 to 15 mm (OR = 3.820/P = .005; OR = 2.220/P = .048, respectively). The C-index of the nomogram model and internal validation were .778 and .768, respectively. In addition, a sample online calculator for the nomogram prediction model had been created (https://docliqi.shinyapps.io/dynnom/).

Indications for cholecystectomy in patients with gallbladder polyps with a long diameter of 10 to 15 mm should be assessed by combining the information on short diameter, number of polyps, fundus, and echogenicity. The nomogram model can be used to predict the risk for the development of gallbladder polyps with malignant tendency.