Review of radiological classifications of pancreatic cancer with peripancreatic vessel invasion: are new grading criteria required?

Pancreatic cancer is mainly diagnosed at an advanced stage when adjacent vessel invasion is present; however, radical resection is potentially curative for selected patients with adjacent vessel invasion. Therefore, accurately judging the resectability of patients with adjacent vessel invasion represents a crucially important step in diagnosis and treatment. Currently, decisions regarding resectability are based on imaging studies, commonly contrast computed tomography (CT). Several radiological classifications have been published for vascular infiltration in pancreatic cancer. However, radiologists always formulate these CT grading systems according to their own experience, resulting in different judgment methods and parameters. And it is controversial in evaluating performance and clinical application. Besides, the conventional CT grading systems mainly focus on the evaluation of vessel invasion so as to less on the outcome of patient evaluation. In this review, we summarize the mainstream CT grading systems for vascular invasion in pancreatic cancer, with the aim of improving the clinical value of CT grading systems for predicting resectability and survival.