High predictive ability of apparent diffusion coefficient value for wall-invasion pattern of advanced gallbladder carcinoma.

PURPOSE: The wall-invasion pattern classification of advanced gallbladder carcinoma (GBC) has been reported. However, its association with clinical findings remains unclear. We aimed to clarify relationships between clinicopathological characteristics, prognosis, and apparent diffusion coefficient (ADC) values of advanced GBC based on the wall-invasion pattern.

METHODS: We reviewed the data of 37 patients who had undergone advanced GBC cholecystectomy at our institution between 2009 and 2021. Clinicopathological findings, prognosis, and ADC values were retrospectively analyzed.

RESULTS: Based on the wall-invasion pattern, patients were classified into infiltrative growth (IG) type (n = 22) and destructive growth (DG) type (n = 15). In the DG-type, the incidence of venous invasion (P = 0.027), neural invasion (P = 0.008), and lymph node metastasis (P = 0.047) was significantly higher than in the IG-type, and recurrent-free survival (RFS) was significantly shorter (P = 0.015); the median RFS was 11.4 months (95% confidence interval, 6.3-16.5 months) in the DG-type and not reached in the IG-type. The ADC value in the DG-type was significantly lower than in the IG-type (median, 1.19 × 10-3 mm2 /s vs. 1.86 × 10-3 mm2 /s, P < 0.001). The area under the receiver operating characteristic curve for the ADC values to differentiate wall-invasion patterns was 0.95 (95% confidence interval, 0.87-1.00). The optimal cutoff ADC value was 1.45 × 10-3 mm2 /s (sensitivity, 92.9%; specificity, 90.9%).

CONCLUSIONS: The wall-invasion pattern of advanced GBC is associated with its aggressiveness and prognosis, and can be predicted by ADC values with high accuracy.