Use of PET Imaging to Distinguish Malignant From Benign IPMN

Intraductal papillary mucinous neoplasm (IPMN) is a cystic pancreatic lesion that is a precursor to invasive pancreatic cancer. Differentiating whether an IPMN lesion is benign or malignant is critical, as the prognosis and management differs drastically, varying from surgery to clinical observation. However, despite physicians' attempts to characterize features concerning for malignancy, it is difficult to determine the likelihood of malignancy with conventional imaging techniques, and an accurate and non-invasive test to identify malignant IPMN is needed. Our hypothesis is that positron emission tomography (PET), a three-dimensional imaging that can identify cancer cells through their increased use of sugars, may be a superior test for differentiating between benign and malignant IPMN lesions. The investigators are planning a prospective pilot study of patients with IPMN who are undergoing surgery for their disease. These patients will undergo PET imaging, as well as computed tomography (CT), magnetic resonance imaging (MRI), and endoscopic ultrasound (EUS) as clinically indicated. Samples of tissue removed during surgery will be assessed and will serve as the gold standard for determining whether the lesion is benign or malignant. The investigators will evaluate the positive and negative predictive values of PET imaging for malignancy within IPMN lesions.

Intraductal papillary mucinous neoplasm (IPMN) is a cystic pancreatic neoplasm that is a precursor to invasive pancreatic cancer. Differentiating whether an IPMN lesion is benign or malignant is critical, as the prognosis and management differs drastically, varying from surgical resection to observation. However, despite attempts to characterize features concerning for malignancy, it is difficult to determine the likelihood of malignancy with conventional imaging techniques, including CT, MRI, and EUS. An accurate, non-invasive test to identify malignant IPMN is needed. The investigators' hypothesis is that \[18F\]-FDG PET may be a superior modality for differentiating between benign and malignant IPMN lesions. We are planning a prospective pilot study of ten consecutive patients with IPMN from the Columbia University Pancreas Center who are undergoing surgical resection for their disease. These patients will undergo \[18F\]-FDG PET imaging, as well as CT, MRI, and EUS as clinically indicated. All scans will be reviewed by two experienced nuclear medicine radiologists who will be blinded to the clinical characteristics of study patients and who will reach a consensus. Areas of focally increased \[18F\]-FDG intake will be identified. Side-by-side reading with CT scan will be performed to evaluate whether the increased \[18F\]-FDG uptake corresponds to a pancreatic lesion. Mean and maximal standardized uptake value (SUV) values, as well as differences in intensity between the region of interest and the remaining pancreas, will be calculated.Surgical pathology will be utilized as the gold standard for histological determination. Standard post-operative histological interpretation of each IPMN lesion will be recorded, including size, duct involvement (main, side, or mixed), ductal dilatation, lesion location (head, neck, body, tail), and histologic grade (adenoma, borderline, carcinoma in situ, invasive carcinoma). In addition, any associated pancreatitis or any other non-IPMN neoplastic change will also be noted. Using PET scan results and surgical pathology information, we will evaluate the positive and negative predictive values of \[18F\]-FDG PET for malignancy within IPMN lesions.