Comparative Accuracy of Tumor Size Assessment and Stage Analysis by Imaging Modalities Versus Gross Examination for Pancreatic Ductal Adenocarcinoma.

OBJECTIVES: Tumor size has been shown to be a strong predictor of patient survival in pancreatic ductal adenocarcinoma (PDAC). The aims of this study were to assess the consistency of preoperative imaging and gross examination for PDAC tumor size measurement and to evaluate the impact on T and overall tumor staging when size measurements by imaging and gross examination were different.
METHODS: Patients diagnosed with PDAC who underwent pancreaticoduodenectomy or distal pancreatectomy from 2007 to 2017 were retrospectively reviewed. A total of 268 cases were included.
RESULTS: Imaging studies underestimated tumor size in comparison with gross examination. Staging the tumors based on imaging size using the eighth edition American Joint Committee on Cancer resulted in an altered T stage in 106 cases (39.6%). There was no T-stage change in the remaining 162 cases (60.4%) despite the presence of variable size discrepancies (0.1-1.7 cm). When nodal metastases were also considered, there was no change in the overall tumor stage in most cases.
CONCLUSIONS: Although discrepancies exist between tumor size measurements by imaging modalities and gross examination, which may result in an altered T stage in a substantial number of cases, the overall tumor stage is only rarely altered.