Introduction to Pancreatic Cancer
Pancreatic ductal adenocarcinoma constitutes 90% of all primary malignant tumors arising from the pancreatic gland, and it is a highly lethal malignancy, which is increasing in incidence and mortality. In up to 60–70%, the tumor is located in the head, and the remaining is equally distributed in the body and in the tail of the pancreas. Due to aggressiveness of the tumor, the diagnosis of pancreatic cancer (PC) is rarely made at an early stage. More than 90% of PCs appear in the late stage of disease, and only 10% of patients have resectable tumors at the time of diagnosis. This is one of the main reasons for failing to achieve a cure in most patients since the only potentially curative therapy for pancreatic carcinoma is complete surgical resection.
The goal of pancreatic imaging is the early detection and characterization of clinically relevant pancreatic lesions. Incidental pancreatic lesions are increasingly common and can range from benign incidental lesions to malignant. Consequently, in some cases the detection of a mass on imaging is nonspecific, and 5–15% of pancreatic resections may show benign pathology given the significant overlap of patient symptoms in benign and malignant pancreatic disorders. In addition, no pancreatic mass is visualized on imaging evaluation in 10% of cases since the tumor may be isoattenuating . Thus, the presence and location of a mass may be assumed from secondary signs such as mass effect, an abnormal convex contour of the pancreas, ductal obstruction, and vascular invasion. Therefore, the use of a multimodality approach combines the strengths of individual imaging modalities and has a synergistic effect in improving diagnostic yield. Imaging techniques currently used for diagnosis and preoperative staging of PC include transabdominal ultrasound (US), contrast-enhanced multidetector computed tomography (MDCT), magnetic resonance imaging (MRI), MR cholangiopancreatography (MRCP), and PET scan and invasive imaging modalities like endoscopic ultrasound (EUS), endoscopic retrograde cholangiopancreatography (ERCP), and intraductal ultrasound (IDUS) .