Endoscopic Ultrasound and Pancreatic Cancer Screening
Many studies show that EUS has a significant benefit over risk ratio, although more data is needed to fully understand the potential of EUS in screening for pancreatic cancer.
Pancreatic adenocarcinoma is the fourth most lethal malignancy for men and women in the United States.1 Patients can present with a multitude of non-specific symptoms, including weight loss and jaundice with and without abdominal pain. At the time of presentation, only 10-20% of patients will be diagnosed with a stage that is amenable to surgical resection and potential cure.2
Up to 10% to 15% of pancreatic cancers are associated with an underlying genetic etiology.3,4 There is still is some debate as to the exact patient population to screen and which screening test(s) are the most accurate and cost-effective.
There are several available methods to screen high-risk patients for pancreatic cancer. These include bloodwork (biomarkers such as carbohydrate antigen [CA] 19.9), abdominal imaging studies (ultrasound, magnetic resonance imaging [MRI]/magnetic resonance cholangiopancreatography [MRCP], computed tomography [CT]) and endoscopic procedures (endoscopic ultrasound [EUS] and endoscopic retrograde cholangiopancreatography [ERCP]). With significant data accumulating, EUS is a screening test with a significant amount of clinical potential.
During an EUS, patients are given anesthesia. The echoendoscope used is very similar to the traditional scopes used to perform an esophagoduodenoscopy (EGD), except that it has a small ultrasound probe at the tip of the scope. The echoendoscope is passed through the patient's mouth into the esophagus, stomach, and up to the second part of the duodenum. The ultrasound probe at the end of the echoendoscope is then used to examine the pancreas for any abnormalities in the parenchyma, ducts, surrounding blood vessels, and lymph nodes. If a suspicious lesion is identified, a fine needle aspiration (FNA) can be performed to obtain a sample for cytology analysis.
The International Cancer of the Pancreas Screening (CAPS) Consortium identified EUS as the best initial screening test (along with MRI/MRCP). A study leading up to the CAPS Consortium showed that EUS had the highest detection rate of pancreatic abnormalities among high risk patients (42.6%), compared to CT (11%) and MRI/MRCP (33.3%).5 The reported sensitivity (89% to 92%) and specificity (96%) of EUS with FNA pancreatic cancer is extremely high, according to 2 large meta-analyses.6,7
EUS has several advantages over other screening methods. If suspicious lesions are identified during the EUS, they can be sampled during the procedure, which is typically not the case during trans-abdominal ultrasounds, MRI/MRCP or computerized tomography (CT) scans of the abdomen. Unlike CT, EUS does not expose patients to radiation or intravenous contrast.
The risks are similar to an EGD and include infection, bleeding and perforation. EUS also carries an additional risk, albeit small, of pancreatitis. EUS carries the risk of anesthesia-related complications.
Many studies show that EUS has a significant benefit over risk ratio, although more data are needed to fully understand the potential of EUS in screening for pancreatic cancer.
- Siegel RL, Miller KD, Jemal A. Cancer statistics, 2016. CA Cancer J Clin. 2016;66(1):7-30. doi: 10.3322/caac.21332
- Poruk KE, Firpo MA, Adler DG, Mulvihill SJ. Screening for pancreatic cancer: why, how, and who? Ann Surg. 2013;257(1):17-26. doi: 10.1097/SLA.0b013e31825ffbfb
- Canto MI, Harinck F, Hruban RH, et al. International Cancer of the Pancreas Screening (CAPS) Consortium summit on the management of patients with increased risk for familial pancreatic cancer. Gut. 2013;62(3):339-47. doi: 10.1136/gutjnl-2012-303108
- Chari ST, Kelly K, Hollingsworth MA, et al. Early detection of sporadic pancreatic cancer: summative review. Pancreas. 2015;44(5):693-712. doi: 10.1097/MPA.0000000000000368
- Canto MI, Hruban RH, Fishman EK, et al. Frequent detection of pancreatic lesions in asymptomatic high-risk individuals. Gastroenterology. 2012;142(4):796-804 doi: 10.1053/j.gastro.2012.01.005
- Chen J, Yang R, Lu Y, Xia Y, Zhou H. Diagnostic accuracy of endoscopic ultrasound-guided fine-needle aspiration for solid pancreatic lesion: a systematic review. J Cancer Res Clin Oncol. 2012;138(9):1433-41. doi: 10.1007/s00432-012-1268-1
- Puli SR, Bechtold ML, Buxbaum JL, Eloubeidi MA. How good is endoscopic ultrasound-guided fine-needle aspiration in diagnosing the correct etiology for a solid pancreatic mass?: A meta-analysis and systematic review. Pancreas. 2013;42(1):20-6. doi: 10.1097/MPA.0b013e3182546e79