Fine-Needle Biopsy of Pancreatic Masses

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The summary below is from the full report titled "Endoscopic Ultrasonography–Guided Fine-Needle Aspiration Biopsy of Suspected Pancreatic Cancer." It is in the 20 March 2001 issue of Annals of Internal Medicine (volume 134, pages 459-464). The authors are F Gress, K Gottlieb, S Sherman, and G Lehman.

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. An abnormal growth (mass) in the pancreas can be cancer or a benign (noncancerous) tumor. Finding out whether a pancreatic mass is cancer usually involves biopsy—putting a thin needle into the pancreatic mass to obtain a tissue sample that can be examined under a microscope. One way to do needle biopsies is to use an ultrasound instrument, which makes images of the pancreas that help identify the best place for the biopsy. The ultrasound images can be made either by passing the ultrasound instrument across the outside of the abdomen or by using an instrument built into a tube (endoscope) that gets passed through the patient's mouth into the stomach (endoscopic ultrasound). Unfortunately, no biopsy method is perfect, and some methods miss as many as 20% of pancreatic cancers.

Why did the researchers do this particular study?

To see whether fine-needle biopsies of the pancreas guided by endoscopic ultrasound are effective at finding cancer in patients whose previous biopsies using other methods did not show cancer.

Who was studied?

102 patients with suspected pancreatic cancer. All of the patients had previous negative results on biopsies that had used methods other than endoscopic ultrasound.

How was the study done?

The researchers used endoscopic ultrasound in all study patients to locate the pancreatic mass. A physician used a fine needle to take one or more biopsy samples from the site identified by ultrasound. A pathologist examined the biopsy samples under a microscope to look for cancer cells.

What did the researchers find?

Biopsy results showed cancer cells in 57 of the 102 patients. All of these patients subsequently died of pancreatic cancer. Of the remaining patients, 37 had negative biopsy results and 8 had inconclusive findings. Four of the patients with negative or inconclusive biopsy findings were found to have pancreatic cancer at surgery; the other 41 patients had no evidence of pancreatic cancer 5 to 48 months later. Three patients had minimal bleeding or inflammation of the pancreas after their biopsy.

What were the limitations of the study?

This study was not large, and all patients were evaluated because of a strong suspicion for cancer of the pancreas. The physicians who did the biopsies and who read the biopsies were aware of this strong suspicion and may have made extra effort to find pancreatic cancer.

What are the implications of the study?

Fine-needle biopsies guided by endoscopic ultrasound may be useful for evaluating pancreatic masses, particularly when other biopsy methods have had negative results and pancreatic cancer is still suspected.