April 27, 2017
Saowanee Ngamruengphong uses endoscopic submucosal dissection to resect entire rectal tumors rather than snare them in pieces.
Johns Hopkins among the few U.S. centers to offer innovative procedure
Looking at results from high-definition scopes, enhanced imaging, endoscopic ultrasound and other advanced diagnostic tools, Johns Hopkins’ multidisciplinary teams work together on personalized care plans for patients with gastric cancer. Most times, when resection is necessary, common endoscopic mucosal resection (EMR) is sufficient.
But when patients require something more complex, gastroenterologist Saowanee Ngamruengphong and colleagues offer other options.
For 10 weeks last summer, she studied advanced endoscopic early-cancer removal techniques at the place where they perform the procedures several times a day: Tokyo’s National Cancer Center, the world’s foremost facility for innovative endoscopic removal of gastric cancers.
Gastric cancer is far less common in North America than in Eastern Asia, which sees 50 percent of all new cases worldwide each year. The Japanese center's faculty teaches the latest endoscopic resection techniques annually to only a few physicians from around the world.
Ngamruengphong spent her time there learning endoscopic submucosal dissection (ESD), as well as detection, evaluation and treatment of all kinds of early luminal cancers and precancers.
She says that EMR, the most common approach in the U.S., is not always the appropriate one for complex, large or difficult-to-reach dysplasia. This technique uses the endoscopic snare to resect lesions a piece at a time.
"But with ESD, you can resect no matter the size," says Ngamruengphong. "And you can tell if it's curative, which EMR cannot do."
ESD uses endoscopy to accomplish what, not long ago, could only be achieved with open surgery. By separating the intestinal lining from the muscle wall, taking great care against any perforations, Ngamruengphong can excise tumors that have not entered the muscle layer.
"It's very delicate," she says. "You need a high-definition scope. And you use an endoscopic knife to separate the muscle from the submucosa."
For larger, more invasive cancers, Ngamruengphong performs full thickness resection, which involves gathering up cancerous or precancerous tissue, as well as the area around it, then using a clip to isolate it. Ngamruengphong says she usually sutures the bottom of the gathered-up tissue and cuts just above the suture. Because the excision is already closed, there is very little bleeding and patients seldom require hospital admission.
"We send the whole resected tissue to pathology, looking for clear margins," she says.
She describes a recent procedure as typical.
"The patient had a four-centimeter tumor in her colon. We removed it and sutured it," Ngamruengphong says. "The patient went home after the procedure."
Pathology found that the tissue was malignant. "But because we got the foci of cancer and the margins were clear, all she requires now is follow-up monitoring for recurrence."
Because she used the endoscopic knife rather than the snare, she was able to remove the whole tumor.
"In the past, that would have come out in about 20 pieces," Ngamruengphong says. "It would have been impossible for pathologists to tell us whether we got it all."