According to a study published in the American Journal of Gastroenterology, patients who are suspected of having pancreatic cancer, but who have a negative endoscopic ultrasound, most likely do not have pancreatic cancer and can be spared further diagnostic testing.
The pancreas is an organ surrounded by the stomach, small intestine, bile ducts, gallbladder, liver, and spleen. It helps the body to break down food and produces hormones (such as insulin) to regulate the body’s storage and use of food.
Pancreatic cancer is the fourth leading cause of cancer death in the US. The diagnosis and staging of pancreatic cancer often involves the use of endoscopic ultrasound (EUS). EUS involves the insertion of a tube (the endoscope) into the stomach. An ultrasound machine attached to the endoscope sends sound waves to the pancreas. EUS has been shown to be particularly useful for detecting small pancreatic tumors, but it’s uncertain to what extent a negative test rules out pancreatic cancer.
In order to determine the frequency of pancreatic cancer in patients with a negative EUS, researchers evaluated 693 patients who were suspected of having pancreatic cancer and who had undergone EUS. Symptoms that prompted EUS included weight loss, abdominal pain, abnormal imaging (an abnormal CT scan, for example), and abnormal lab tests.
A total of 155 patients were found to have a normal pancreas based on EUS. During an average of two years of follow-up, none of these patients developed pancreatic cancer. This suggests that patients who have a negative EUS have a very high likelihood of not having pancreatic cancer. The researchers note that this study was based on EUS performed by expert endosonographers; medical centers that do fewer of these procedures may not achieve the same results.
The researchers conclude that no further diagnostic testing is required for patients with a suspicion of pancreatic cancer, but a negative EUS performed by an expert endosonographer. A negative EUS appears to accurately identify patients without pancreatic cancer. The researchers suggest that EUS should be the initial diagnostic test for patients who are suspected of having pancreatic cancer.
Reference: Klapman JB, Chang KJ, Lee JG et al. Negative predictive value of endoscopic ultrasound in a large series of patients with a clinical suspicion of pancreatic cancer. American Journal of Gastroenterology. 2005;100:1-4.