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

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.