Identification of SMAD4-mutated pancreatic ductal adenocarcinoma using preoperative contrast-enhanced MRI and clinical characteristics.

Aim: To assess the value of preoperatively contrast-enhanced MRI and clinical characteristics for identification of SMAD4-mutated pancreatic ductal adenocarcinoma (PDAC) patients.

Materials And Methods: This retrospective study included patients with surgically confirmed PDAC from January 2016 to December 2022. Based on immunostaining results indicating the mutation of SMAD4, the enrolled participants were grouped into SMAD4-mutated PDAC and non-SMAD4-mutated PDAC. Contrast-enhanced MRI findings, clinical-pathological characteristics, and prognosis were recorded and reviewed. The pathological findings and clinical prognosis were compared between the two groups. Uni- and multivariable logistic regression analyses were further performed to determine the radiological and clinical predictive factors for the mutation of SMAD4.

Results: In total, 428 PDAC patients were enrolled and analyzed, who were grouped as SMAD4-mutated PDAC (n = 224) and non-SMAD4-mutated PDAC (n = 204). SMAD4-mutated PDAC demonstrated higher frequency of pathological fatty infiltration (83.4% vs. 74.2%, P = 0.016), peripheral nerve infiltration (84.4% vs. 76.5%, P = 0.039). and higher recurrence rates (43.6% vs. 58.9%, P = 0.045) than non-SMAD4-mutated PDAC. The 3-year recurrence-free survival rates were worse for SMAD4-mutated PDAC (28.7% vs. 39.1%). In multivariable logistic regression analyses, CA19-9 > 100 U/mL (odds ratio [OR] = 1.519, P = 0.041), CBD dilation (OR = 1.564, P = 0.036), and rim enhancement (OR = 1.631, P = 0.025) were independent predictive factors.

Conclusion: Rim enhancement, CBD dilation on contrast-enhanced MRI and higher CA19-9 level are promising radiological and clinical factors for identifying SMAD4-mutated PDAC.