Secretin (ChiRhoStim) Pancreas Perfusion for Pancreatic Adenocarcinoma

The purpose of this study is to test if secretin-enhanced CT is a useful noninvasive screening tool for pancreatic cancer in a high-risk population.

Pancreatic cancer is the fourth most common cause of cancer death in the US. Because patients with pancreatic cancer rarely presents with disease specific symptoms until late in the course of the disease, identifying and developing surveillance strategies for early detection of asymptomatic pancreatic cancer is critical. EUS and fine needle aspirate (FNA) are currently the most accurate non-operative methods of establishing the presence or absence of pancreatic cancer.

The CT findings of pancreatic cancer include an attenuation difference between the pancreatic mass and the surrounding pancreatic parenchyma, pancreatic ductal dilation and cutoff, disruption of the normal fatty marbling of the pancreatic parenchyma, rounding of the inferior margin of the posterior head of the pancreas, atrophy of the proximal gland, and signs of locally advanced or distant disease. In a case-controlled retrospective review of pancreatic cancers missed at CT prior to clinical presentation at the Mayo Clinic, Gangi et al found that CT findings definite or suspicious for pancreatic cancer were present in 50% of scans obtained up to 18 months before the clinical diagnosis of pancreatic cancer. Pancreatic duct dilation and cutoff were early CT findings indicating tumor presence, and were associated with near-perfect and substantial interobserver agreement. Consequently, early pancreatic neoplasms likely result in at least partial occlusion of the duct, leading to subsequent ductal dilation.

We hypothesize that increased production of the pancreatic juice distends the otherwise small caliber pancreatic duct, and accentuate the secondary sign of pancreatic duct obstruction by a small pancreatic mass. The investigators will be able to take advantage of this physiologic effect of secretin, by obtaining multi-planar scans with isotropic resolution using a 64-channel CT system.

Secretin is a safe agent that increases pancreatic exocrine secretion. Intravenously administered secretin increases the pancreatic juice secretion, and magnetic resonance or CT scan obtained after secretin has been shown to improve visualization of the pancreatic duct.

Day 1: Patient will fast 4 hours prior to the study. 1 L of water is given by mouth as an oral contrast material 30 minutes prior to the study. After placing an angiocath in the antecubital fossa, the patient will be placed in a supine position on the CT scanner.

Secretin test dose will be given intravenously (0.2mcg (0.1ml). If no reaction is noted after one minute, then Secretin will be given intravenously (0.2 mcg/kg IV slowly over one minute). If an allergic reaction is noted, the patient will not have a CT scan performed as part of this study protocol, and that participant will be ineligible to participant with this study. Secretin bolus will be terminated if Systolic BP \< 90mm/Hg is not corrected with IV fluids.

Pre-contrast scan will be obtained with collimation of 0.6 x 64 mm and a pitch of 1.2 through the abdomen under deep inspiration. Images will be reconstructed with 1 mm slice thickness and 2 mm increment.

Five minutes after administration of the intravenous Secretin, iodinated contrasted Omnipaque 350 administered at 3-5ml/sec. Post-iodine-contrast scanning will be obtained with collimation of 0.6 x 64 mm and a pitch of 1.2 through the abdomen with scan delays of 40- and 70-seconds. Total of 150 ml of intravenous iodinated contrast will be administered at the rate of 3 - 5 ml/ sec.

For the 3 month (Day 2) and 18 month (Day 3) follow-up CT imaging:

Patient will fast four hours before scan. 1 liter of water given orally 30 minutes prior to scan. An IV will be placed, and participant will have iodinated contrast (Omnipaque 350) administered at 3-5ml/sec. Post iodine scanning will be done with collimation of 0.6 x64mm and a pitch of 1.2 through the abdomen with scan delays of 40 and 70 seconds.

For the optional CT scan for those who have initial positive CT:

This exam is to be done only before endoscopic ultrasound (EUS). Patient will fast four hours before scan. 1 liter of water given orally 30 minutes prior to scan. An IV will be placed, and participant will have iodinated contrast (Omnipaque 350) administered at 3-5ml/sec. Post iodine scanning will be done with collimation of 0.6 x64mm and a pitch of 1.2 through the abdomen with scan delays of 40 and 70 seconds.

Subjects will be followed up for 3-5 years to determine if they develop pancreatic cancer.

Eligibility Criteria:
Inclusion Criteria:

* Persons 50 years or older with recently diagnosed diabetes (within 2 years), with at least one of the following: no family history of diabetes, abdominal discomfort, anorexia, weight loss, elevated serum CA 19-9, or those undergoing EUS with or without Fine Needle Aspiration (FNA) for pancreatic cancer screening ; OR
* Persons 35 years old or older with familial pancreatic cancer with 2 or more first degree relatives with pancreatic cancer; OR
* Persons 35 years old or older with Peutz-Jeghers syndrome; OR
* Persons 35 years old or older with suspicious clinical symptoms of pancreatic cancer, but had normal CT of the abdomen with iodinated contrast within 2 weeks.

Exclusion Criteria:

* Persons with contraindication to iodinated contrast
* Allergy to iodinated contrast
* Renal insufficiency (serum creatinine \> 1.5 mg/dl)
* Patients with contraindication to ionizing radiation
* Pregnancy
* Patients with previous pancreatic surgery
* Contraindication to secretin
* Allergy to secretin
* Acute pancreatitis