Accuracy of gallbladder polyp size in predicting and detecting gallbladder cancer-a single-center study on gallbladder polyps

Abstract

Abstract Background: Despite the fact that most gallbladder polyps are benign, malignant lesions are not so rare as thought. We performed this study to evaluate size distribution of gallbladder polyps and assess efficiency of reported risk factors in predicting malignancy. Methods: In this study, medical records of patients having undergone laparoscopic cholecystectomy for gallbladder polyps at Department of Hepatobiliary and Pancreatic Surgery, Shenzhen People,s Hospital were reviewed. Chi-square test and binary logistic regression analysis were adopted to determine risk factors for malignant lesions. Additionally, receiver operating curve (ROC) analysis was accomplished to identify the optimal cutoff size. Results: A total of 1012 patients were included in this study. Of the 1012 patients, 977 ones were diagnosed with benign gallbladder polyps while 35 ones with malignant polyps. Diameters of the 977 benign gallbladder polyps were between 1 and 50 mm while the 35 malignant polyps were between 4 and 54 mm. Incidence of gallbladder cancer among lesions ≥10mm was 15.5%, 31.5% for lesions ≥15mm and 49.0% for lesions ≥20mm. Among polyps in the following four size ranges (≤5mm, 6-9mm, 10-14mm, and 15-19mm), cholesterol polyps were the most common. While among polyps between 20 and 24mm, adenomas were the most common and among polyps ≥25mm, malignant tumors were the most common. Sessile morphology was significantly more common in malignant lesions (91.4%) than in benign lesions (3.7%, P<0.001). Multiple polyps were frequently diagnosed not only as cholesterol polyps (82%) but also as adenomas (4.3%) and gallbladder cancer (0.3%). We demonstrated that sessile morphology, blood flow signal on ultrasonography and single polyps were independent predictive factors for gallbladder malignancy. Conclusions: Detection rate of malignant lesions increased significantly with the increase in diameter. Risk factors such as sessile morphology, blood flow signal on ultrasonography and single polyps were effective factors predicting malignant lesions. It was difficult for us to accurately confirm the pathological diagnoses of gallbladder polyps solely based on preoperative examinations given the fact that cholesterol polyps and adenomas were quite common, even among large gallbladder polyps.