Gallbladder polyps growth rate is an independent risk factor for neoplastic polyps

Abstract

Background: The size of gallbladder (GB) polyps is a representative risk factor for neoplastic polyps. However, whether growth rate during follow-up is associated with neoplastic polyps remains unclear.

Methods: From 2009 to 2019, a cohort of patients with GB polyps who underwent cholecystectomy was enrolled. We included only patients who underwent at least two abdominal ultrasonography procedures at least 6 months apart prior to cholecystectomy. Performance and optimal cutoff value of polyp growth rate for predicting neoplastic polyps were estimated using receiver operating characteristic (ROC) analysis. In addition to growth rate, several other variables considered suitable for predicting neoplastic polyps were also investigated. A nomogram was created to predict neoplastic polyps.

Results: A total of 239 patients with neoplastic polyps (n = 27, 11.3%) and non-neoplastic polyps (n = 212, 88.7%) were included. The median follow-up period was 28.5 months. The area under the ROC curve (AUROC) of polyp growth rate for neoplastic polyps was 0.66 (95% confidence interval, 0.59-0.72). The growth rate cutoff value for prediction of neoplastic polyps was 3 mm/year (sensitivity, 37.0%; specificity, 86.3%). Multivariate analysis identified several factors predicting neoplastic polyps: polyp size ≥10 mm (odds ratio [OR], 3.74, p = 0.041), solitary polyp (OR, 3.92, p = 0.004), and polyp growth rate ≥ 3 mm/year (OR, 2.75, p = 0.031). The AUROC of the nomogram using these three significant factors in multivariate analysis was 0.71.

Conclusion: GB polyps with a growth rate of over 3 mm per year on ultrasonography during follow-up should be considered a risk factor for neoplastic polyps.

Keywords: gallbladder polyp; growth rate; neoplastic polyp; risk factor; ultrasonography.