The influence of time interval between diagnostic image acquisition and operative date on pathologic tumor size in pancreatic adenocarcinoma: implications for local therapy

Objectives: Computed tomography (CT) and magnetic resonance imaging (MRI) may underestimate pancreatic tumor size, which has important implications for local therapy. Our aim was to determine if tumor growth during the interval between image acquisition and operative date impacted the observed size discrepancy. Methods: Tumor sizes measured on preoperative MRI were compared with gross pathological specimen measurements in 148 patients with surgically resected pancreatic adenocarcinoma. Differences in the measurements were correlated with the interval between date of pre-operative MRI acquisition and date of operation. Differences between tumor size on MRI and pathology reports were compared with respect to the intervening time interval. Results: A total of 148 patients had pre-operative MRI scans and were included in the analysis. The median patient age was 66 years (range: 29 years-86 years). A significant under estimation of 4.5 mm between tumor size measured on preoperative MRI and pathological examination ( p < .001) was demonstrated. There was no significant correlation between size discrepancy and time interval from the diagnostic imaging study and the surgical procedure (R 2 = 0.001, p = .72). Conclusions: Time interval between the acquired diagnostic imaging study and operative date appears to have no measureable influence on radiographic to pathologic size discrepancy in pancreatic adenocarcinoma. MRI was again shown to underestimate pancreatic cancer tumor size. Additional exploration into the role of MRI in delineating pancreatic tumor volume with a prospectively designed study is needed to validate these findings.