California Pacific Currents 2001
Center of Excellence in Endoscopic Diagnosis and Therapy
Advances in research lead to improvements in clinical care, and Kenneth Binmoeller, MD, a gastroenterologist, has made contributions to each environment that have earned him national and international distinction. Dr. Binmoeller has performed complex interventional endoscopic procedures since the late 1980s when he completed a clinical fellowship at the Oregon Health Sciences University in Portland. After his fellowship, he held positions both in Europe and the United States. Currently, he is the medical director of Interventional Endoscopy Services at California Pacific Medical Center and is developing a plan for an advanced interventional endoscopy program at the Medical Center.
An endoscope is a small, flexible fiber optic tube with a light and a lens on the end that is used to view the inside of an organ or cavity such as the esophagus, stomach, duodenum, colon, or rectum. Miniature endoscopes, with a diameter barely larger than a matchstick, can even be passed into the bile and pancreatic ducts. “Advances in the field of interventional endoscopy have been remarkable, enabling us to diagnose and treat diseases with the flexible endoscope,” comments Dr. Binmoeller. “Patients benefit enormously from the minimally invasive approach that endoscopy affords, in part because they do not receive general anesthesia for the procedure. The avoidance of more invasive procedures also results in substantial cost savings. The creation of a new interventional endoscopy service at California Pacific is timely and visionary.”
According to Martin Brotman, MD, president and CEO of the Medical Center, “In an era of interdisciplinary health care, the provision of interventional endoscopy represents a component of our overall strategy to make California Pacific one of the leading centers of excellence in the United States for the management of pancreatic disorders, liver disease, gastrointestinal oncology, and colorectal disease.”
The Research Agenda
A research agenda for interventional endoscopy is already mapped out and includes magnification endoscopy, endoscopic ultrasonography, super glue, and endoscopic clips. Proposed research studies will evaluate the feasibility, efficacy, and safety of these state-of-the-art technologies and procedures.
Zooming in to Detect Cancer
New technology, known as the “zoom” endoscope, can magnify up to 100 times, enabling the detection of subtle tissue irregularities in the gastrointestinal (GI) tract. Such irregularities can represent cancerous or precancerous change. “Most GI cancers originate from the surface or mucosal layer of the bowel wall. Thus, the endoscopist has a unique opportunity to detect cancer at an early stage when cure is still possible,” says Dr. Binmoeller, one of only a handful of investigators in the world evaluating zoom endoscopes to improve the detection of cancer.
Enhanced magnification endoscopy utilizes a contrast agent in addition to the zoom endoscope to improve the detection of malignant and premalignant tissue. In Japan, where cancers of the esophagus and stomach are commonly seen, special dyes are used to highlight small, flat cancers. Data from Japan have shown that small, flat lesions are far more likely to be cancerous or precancerous than the more readily identified polyp-shaped lesions.
Dr. Binmoeller is investigating the use of enhanced magnification endoscopy to identify areas of cancerous change in patients with Barrett's esophagus, a premaligant condition that is associated with chronic gastroesophageal reflux disease (heartburn). “About one percent of patients with Barrett's have dysplasia, the earliest stage of malignant transformation. Enhanced magnification endoscopy assists in the detection of dysplasia, which can then be treated endoscopically,” states Dr. Binmoeller.
Endoscopic Mucosectomy to Resect Cancer
Dr. Binmoeller and his research team are evaluating new techniques to remove GI cancers using the endoscope. Referred to as “mucosectomy,” these techniques involve the complete resection of the mucosal layer using special endoscopic tools. “Mucosectomy was developed for the purpose of obtaining a larger biopsy specimen—so-called ‘strip biopsy'—but evolved into a therapeutic procedure when it was discovered that this technique was capable of completely removing the abnormal cells. Unlike techniques that burn or destroy tissue, mucosectomy has the advantage of providing a tissue specimen for accurate pathology analysis and confirmation of complete resection.”
“Most advances in endoscopy are related to our ability to see the surface of the GI tract better,” states Dr. Binmoeller. “With endoscopic ultrasonography, we are able to look into and beyond the GI wall, thereby opening up a whole new dimension of endoscopic diagnosis.” Pancreatic tumors as small as two or three millimeters are readily visualized with this technique. “The incidence of pancreatic cancer is rising and early detection is our best weapon.” Because pancreatic cancer has a strong genetic component, Dr. Binmoeller is conducting a study to evaluate endoscopic ultrasonography as a screening tool in patients with a family history of pancreatic cancer.
Endoscopic ultrasonography also allows the endoscopist to guide needles through the gut wall in order to treat surrounding structures. Dr. Binmoeller's research focuses on novel instruments, techniques, and procedures such as the drainage of pancreatic pseudocysts and the establishment of celiac ganglion nerve blocks for chronic pain syndrome. “What is particularly exciting is using endoscopic ultrasonography to guide the injection of chemotherapeutic agents or gene therapy to treat cancers,” says Dr. Binmoeller.
New Applications for Flexible Endoscopes
As surgical instruments for flexible endoscopy improve, new therapeutic applications evolve. One example is the endoscopic incision of a Zenker's diverticulum, an outpouching or herniation caused by increased pressure in and around the upper esophagus. Zenker's diverticulum can cause progressive symptoms of dysphagia (difficulty in swallowing) and regurgitation of food. Dr. Binmoeller is the only physician in the United States performing successful flexible endoscopic treatment on patients with Zenker's diverticulum.
Super Glue for Gastric Varices
Gastric varices (stretched veins in the stomach) are generally unresponsive to standard endoscopic treatments. Dr. Binmoeller pioneered a new endoscopic treatment for gastric varices using Histoacryl, a “GI super glue.” When injected into a varix, Histoacryl immediately hardens and closes the hole in the vessel. This stops active bleeding and prevents rebleeding of the varix. “Our data from the University of Hamburg in
over 300 patients showed a nearly 100 percent hemostasis rate and a remarkably low rebleeding rate of only 5 percent,” says Dr. Binmoeller. Histoacryl has not yet been approved by the FDA in this country and therefore is being used in an investigative protocol at California Pacific.
Other projects in the area of variceal bleeding include the evaluation of the safety and efficacy of lanreotide, an investigational drug for the control of acute bleeding and the prevention of rebleeding from esophageal varices. The drug is given as an adjunct to endoscopic band ligation, the standard treatment for esophageal varices. Band ligation involves the placement of rubber bands over varices in the esophagus to ligate (strangulate) the blood flow. Pressure from the bands causes the varix to close up and scar.
Clips for Bleeding
Another technique pioneered by Dr. Binmoeller is endoscopic clipping. Clips are used to grasp, compress, and close off a bleeding vessel. The bleeding stops immediately and there is no injury to surrounding tissue. Dr. Binmoeller is investigating the use of clips for new indications, such as the closure of tissue defects (tears, perfo- rations) and to affix devices to the bowel wall.
Ductoscopy Using a “Babyscope”
In ductoscopy—endoscopy of the bile and pancreatic ducts—a miniature endoscope, or “babyscope,” is passed through a “mother” endoscope into the targeted duct. Apart from visualizing the interior of the duct, various miniature instruments can be passed through the babyscope for interventional procedures such as tissue sampling and lithotripsy (fragmentation) of stones. “Just as radiologic imaging of the GI tract has been replaced by endoscopy, I predict that radiologic imaging of the bile and pancreatic ducts will one day be replaced by ductoscopy,” states Dr. Binmoeller.
Beyond the Clinical Setting
“In addition to research on new technology, outcomes research projects are planned,” says Dr. Binmoeller. Outcome studies will be conducted on the impact of interventional endoscopy on treatment strategy, quality of life, and cost of health care.
Establishment of the Interventional Endoscopy Service and recruitment of Dr. Binmoeller will enable California Pacific to offer patients state-of-the-art endoscopic expertise that is available at only a few centers in the world. The research agenda will continue to assure the excellence of treatment modalities in the clinical environ-ment, as well as relevant advances in the laboratory.