To investigate the surgical indications for polypoid lesions of the gallbladder (PLG).

Clinical data of 388 patients with PLG undergoing cholecystectomy in the Third Affiliated Hospital of Sun Yat-sen University from January 2008 to December 2018 were retrospectively analyzed. The informed consents of all patients were obtained and the local ethical committee approval was received. Among them, 212 patients were male and 176 female, aged from 18 to 80 years, with a median age of 41 years. The optimal threshold value for the diagnosis of benign or malignant lesions was determined by ROC curve. The risk factors for PLG malignancy were identified by Logistic regression analysis. Nomogram was delineated to predict the probability of benign lesions.

The ROC curve showed that a diameter 12.0 mm was the optimal threshold value for the diagnosis of benign PLG and 14.5 mm for the diagnosis of malignant PLG. Logistic multivariate regression analysis revealed that, a diameter <12 mm, multiple lesions, no blood flow and no gallstones detected by preoperative color Doppler ultrasound were the independent influencing factors for benign PLG (OR=2.341, 2.179, 2.159, 2.195; P<0.05). Preoperative color Doppler ultrasound indicated that a diameter ≥12 mm and abnormal blood cholesterol were the independent influencing factors for malignant PLG (OR=9.642, 2.601; P<0.05). The Nomogram of clinical factors for the diagnosis of benign PLG was delineated. The results showed that PLG diameter occupied the greatest weight, anda diameter <12 mm predicted the possibility of benign lesions.

The diameter ≥12 mm may be the optimal surgical indication for cholecystectomy in patients with PLG, which can avoid unnecessary cholecystectomy while ensuring a low misdiagnosis rate of malignant PLG and minimize medical expenses for the patients and society.