Detecting Pancreatic Cancer and Its Spread

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The summary below is from the full report titled "Comparison of Endoscopic Ultrasonography and Multidetector Computed Tomography for Detecting and Staging Pancreatic Cancer." It is in the 16 November 2004 issue of Annals of Internal Medicine (volume 141, pages 753-763). The authors are J. DeWitt, B. Devereaux, M. Chriswell, K. McGreevy, T. Howard, T.F. Imperiale, D. Ciaccia, K.A. Lane, D. Maglinte, K. Kopecky, J. LeBlanc, L. McHenry, J. Madura, A. Aisen, H. Cramer, O. Cummings, and S. Sherman.

What is the problem and what is known about it so far?

The pancreas is an organ located behind the stomach. It produces enzymes that digest food and hormones that regulate blood sugar levels. Cancer of the pancreas is the fourth leading cause of cancer death in the United States. Pancreatic cancer is often difficult to diagnose, and surgical removal of the tumor is the only chance for cure. Unfortunately, many pancreatic tumors spread to lymph nodes, blood vessels, or other tissues before they are diagnosed. These tumors, which cannot be removed entirely by surgery, are called "unresectable."

Doctors use various tests to detect pancreatic masses that might be cancer and to find out whether cancer has spread. Two of these tests are multidetector computed tomography (MDCT) and endoscopic ultrasonography. Multidetector computed tomography is a fast computer scanning technique that provides high-resolution, 3-dimensional images made from x-rays. Endoscopic ultrasonography shows ultrasound images made by echoes of high-frequency sound waves. The ultrasound instrument is built into a tube (an endoscope) that is passed through the mouth into the stomach near the pancreas. We do not know which test better identifies patients with pancreatic cancer that may be cured by surgery.

Why did the researchers do this particular study?

To see whether MDCT or endoscopic ultrasonography better detects pancreatic cancer and its spread to surrounding lymph nodes, tissues, and blood vessels.

Who was studied?

120 adults with known or suspected pancreatic cancer that had not obviously spread to distant tissues.

How was the study done?

Patients were referred to a hospital where they had endoscopic ultrasonography followed by MDCT within 1 week. These tests were interpreted independently (without knowledge of the other test's result). Surgeons then examined patients, reviewed results of all tests, and recommended surgery for those with no test evidence of advanced cancer or distant spread. Proven pancreatic cancer was diagnosed if surgery or a needle biopsy done during endoscopic ultrasonography had detected cancer or if cancer was confirmed in any way during a 2-year follow-up period. The researchers then compared endoscopic ultrasonography and MDCT findings in patients with proven cancer and among patients whose tumors at surgery were found to be resectable and unresectable.

What did the researchers find?

Multidetector computed tomography and endoscopic ultrasonography detected pancreatic masses in 86% and 98%, respectively, of the 80 patients with proven pancreatic cancer. Among 53 patients undergoing surgery, endoscopic ultrasonography was more accurate than MDCT for detecting tumor spread to surrounding tissues and blood vessels. Both tests showed similar accuracy for detecting the spread of cancer specifically to lymph nodes. Both tests also correctly identified about 90% of the resectable tumors and about 65% of the unresectable tumors.

What were the limitations of the study?

The study was not large and was done at a single hospital. Findings might differ at other sites, depending on the expertise of the persons who perform and interpret the tests.

What are the implications of the study?

Endoscopic ultrasonography more often detected pancreatic masses in patients with proven cancer than did MDCT. Both tests performed similarly in identifying cancers that were resectable.