Tiny scope is a big advance for GI cancers

Last year, when Harry Aslanian, M.D., associate professor of medicine, first looked at images produced by a new diagnostic device known as a confocal laser endomicroscope, he saw what no one had seen before: stunning, high-resolution images of cells, individual red blood cells within vessels, and scar tissue within a pancreatic tumor, all magnified 1,000 times.

For the first time, a miniaturized prototype microscope was passed into a pancreatic mass via a small needle that traveled through the stomach wall, obtaining amazing real-time pictures of an organ that is notoriously difficult to reach, and tricky to evaluate even by CT scans or MRI.

“The quality was very good,” recalls Aslanian, associate director of endoscopy for Yale Medical Group (YMG), who was taking part in the world’s first visualization of the interior of a pancreatic mass using confocal laser endomicroscopy (CLE).

Aslanian and Uzma Siddiqui, M.D., specialize in combining ultrasound and endoscopy to evaluate and perform biopsies in pancreas disorders. Previously, endosonographic views of the pancreas showed only its overall texture, and needle biopsies were required to examine and stain individual cells outside of the body. Aslanian and Siddiqui are participating in an international trial using CLE to diagnose precancerous pancreatic cysts, which can be surgically removed. “Now we’re in the process of fine-tuning this, making a road map to identify precancerous change,” Aslanian says.

High-resolution confocal microscopes are a mainstay in biomedical research, but they have evolved from what Aslanian calls “tabletop versions” to scopes that measure only 2.5 millimeters in diameter. Yale Cancer Center and Smilow Cancer Hospital at Yale-New Haven are among only a handful of institutions in the world and the only centers in Connecticut using the technology. The microscopes fit through the biopsy channels of many endoscopes, the lighted optical instruments gastroenterologists use, to look deep inside the body to spot cancer and precancerous tissue at their earliest stages of development, when many conditions are curable with surgery.

Doctors at YMG are also using CLE to gain new views of the colon, bile duct, and esophagus. Siddiqui, YMG’s director of endoscopic ultrasound, has used the technique to examine patients with Barrett’s esophagus, a disorder associated with long-term esophageal reflux disease that can be a precursor to esophageal cancer. Siddiqui says the microscopic probe helps her target the most suspicious regions of dysplasia, or precancerous tissue changes. Meanwhile, gastroenterologist Priya Jamidar, M.D., director of endoscopy at YMG, is using CLE to diagnose bile duct tumors, where current tissue sampling techniques are only reliable about half the time.

“It’s an impressive technology that is much less invasive for our patients, providing on-the-spot information that can guide the endoscopic evaluation, and, in some cases, treatment,” says Aslanian. In cases of early esophageal and colon cancer, he says, the earliest tumors can be removed through the scope during the same procedure with the specialized techniques of endoscopic mucosal resection. “The potential for the microscope is that we can look at the cells in real time and identify the ones that are likely to progress to cancer.”