Resected gallbladder polyps: comparison of the 2022 Society of Radiologists in Ultrasound and Joint European Societies Guidelines' diagnostic performance

Abstract

Purpose: To compare the diagnostic performance of the Society of Radiologists in Ultrasound (SRU) and the 2022 Joint European Societies (JES) Guidelines regarding management at presentation of gallbladder polyps ≥ 7 mm.

Materials and methods: All patients with ≥ 7 mm polyps reported on ultrasound scans at a hepatobiliary centre with eventual cholecystectomy over 20 years were retrospectively included. Four blinded radiologists reviewed selected images/clips. Shape and wall-thickening were used to categorize polyps. Imaging and relevant clinical features were used to derive guideline management into binary categories of no follow-up/follow vs refer-to-surgeon. Histological neoplastic polyps were defined as a positive outcome. Reliability, sensitivity, and specificity for both guidelines were tabulated.

Results: One hundred thirty-five patients (mean age 51.9 years, 62 female [45.9%]) with a median polyp size of 12 mm (range 7-45) formed the study cohort. Twenty-eight out of one hundred thirty-five (20.7%) of patients had neoplastic polyps (1 low-grade dysplasia, 5 pyloric gland adenoma, 8 intracholecystic papillary neoplasm, 12 carcinoma in situ/carcinoma, 2 metastases). Pooled kappa values for SRUs and JES's polyp risk categorization were 0.70 (CI: 0.64-0.76) and 0.64 (CI: 0.57-0.71) for intra-observer and 0.41 (CI: 0.35-0.46) and 0.47 (CI: -0.40 to 0.53) for inter-observer agreement. SRU's low and indeterminate risk polyps had an odds ratio of 4.4 (p = 0.002) and 16.9 (p < 0.001) of being neoplastic compared to "very-low risk" polyps. Sensitivity, specificity and AUROC (CI) for SRU were 62% (43-80), 90% (85-95), 0.76 (0.66-0.86), and JES were 90% (79-100), 41% (32-49), 0.66 (0.58-0.73) respectively. The differences between the sensitivity and specificity of the two guidelines were significant (p = 0.002 and < 0.0001, respectively).

Conclusion: For ≥ 7 mm polyps, the SRU guidelines have significantly higher specificity with acceptable sensitivity, whereas the JES guidelines have significantly higher sensitivity with low specificity.

Key points: Question What are the diagnostic performances of the 2022 SRU and the JES guidelines for the management of ≥ 7 mm gallbladder polyps? Findings The SRU guidelines were significantly more specific but less sensitive than the JES guidelines. Clinical relevance For ≥ 7 mm polyps, the 2022 SRU guidelines would result in fewer surgical referrals and may be more applicable to the low-incidence populations of Europe and North America.

Keywords: Gallbladder neoplasms/diagnosis; Polyps; Practice guidelines as topic; Reproducibility of results; Ultrasonography.