Kenneth Chang, M.D.
Head, gastrointestinal oncology, UCI Medical Center; director, Interventional Endoscopy Center; associate professor, gastroenterology
The needle on the television-like screen stabs repeatedly into a round shape that has been identified as a lymph node. The images are shadowy, reminiscent of cloud formations seen on radar sweeps, but one rhythmically throbbing form is unmistakable. It is the beating heart of the patient who lies sedated and sleeping on the narrow table. The heart appears to be an inch or so from the stabbing needle, but the televised image is magnified. It is, in fact, only millimeters away.
In the darkened procedure room at UCI’s Interventional Endoscopy Center. Dr. Phuong Nguyen watches the television monitor intently as she manipulates the buttons and dials that control the endoscope tube and biopsy needle which, with each plunge, removes a minuscule bit of tissue.
The man who trained her, Dr. Kenneth Chang, is head of gastrointestinal oncology and is a recognized world leader in endoscopic ultrasound. The procedure Nguyen is using, and Chang is teaching, is endoscopic ultrasound, which in this case is being used to guide an even newer method, fine-needle aspiration. More sensitive than a CT scan, less invasive than surgery, endoscopic ultrasound offers a way to diagnose cancer earlier and with greater detail than was previously possible. In many cases, it can directly replace surgery while costing only a tenth as much. For the patients who are being spared surgery, like this one, the benefit is in reduced suffering and recovery time.
Chang estimates that it is in use in about 150 hospitals across the country. "About half of those (about 75) are equipped to do fine-needle aspiration, and less than half of that number are actually successfully doing needle biopsy on patients," he says. "They have the biotechnology but not the expertise. Right now, the bottleneck is the training." Chang and Nguyen teach a course in endoscopic ultrasound at UCI Medical Center three times a year. Physicians and nurses come from all around the country to learn this new procedure.
The rarity of this expertise has made Chang in demand as a guest lecturer at the Mayo Clinic and other medical centers. In another effort to get information out to the larger medical world, the UCI group last year put out a CD-ROM titled "Training for Endosonography: An Interactive Learning Tool." It won a first-prize audiovisual award from the American Society of Gastrointestinal Endoscopy, and Chang says even lay people are viewing it for the full-color tour it provides of the human digestive system. The group also has a Web site www.gioncology.com to view the CD-ROM.
A gastrointestinal endoscope is a 5-foot-long, slender tube inserted into the digestive tract either downward through the patient’s mouth or upward through the rectum. A microchip television camera embedded in the tip of the tube transmits crisp, clear images to a television monitor. In vivid color, the large bowel appears as a glistening vault against which the webbed red veins of inflammation or irregular shapes of polyps can clearly be seen. The physician performing the procedure watches the TV monitor for visual feedback, takes video photographs of anything that looks questionable, and removes samples for biopsy.
The addition of ultrasound to the endoscope has meant that the tube now can "see" beyond the membranes that limit the TV image. When endoscopic ultrasound is being used, a second TV monitor displays radar-like black and white shadows that are bounced-back sound waves. These images reveal both organs and lesions within those organs. Pancreatic tumors, for instance, can be seen even when they are as small as six millimeters in diameter. CT scans, the previous-best diagnostic tool, could find tumors no smaller than two centimeters.
Making sense of the shadowy ultrasound pictures requires practice and mental agility. All the images arrive in two dimensions and must be converted in the mind of the physician to their three-dimensional counterparts. What to the layman is a blob with a curving tail, for instance, is to Chang or Nguyen the liver seen from a specific angle.
Asked to compare the deciphering of the deep-body ultrasound images to something the rest of us might do, Chang tries this analogy: "You are riding down a Magic Mountain roller coaster, and someone asks where your car is parked and you have to point to it or, you are in a long, winding tunnel and you have to know where north, south, east and west are."
To the patient on Nguyen’s table, however the man whose beating heart has not been touched by the slender biopsy needle the high-tech procedures are irrelevant. He needs only to know whether the chemotherapy he’s undergone has been effective. The enlarged lymph node found on a CT scan was not a good sign, but a biopsy is needed to be certain. In the past, this patient would have been a candidate for exploratory surgery, but now endoscopic ultrasound can be used instead. Nguyen locates the lymph node and uses the endoscope mounted needle to remove biopsy samples.
The news for Nguyen’s patient is not good: The biopsy reveals continued malignancy. But endoscopic ultrasound has provided both an easier recovery and more information than surgery would have done. Because she can see the living lymph node in its surroundings, Nguyen is able to report "staging" information. Are any tumors or other enlarged lymph nodes seen nearby? Does the liver show signs that the cancer is spreading, or metastasizing?
Tumor staging is critical information in planning treatment (or in some cases, curtailing treatment) and it often is the primary reason endoscopic ultrasound is ordered. Used in cases of esophageal, rectal, pancreatic, gastric and, most recently, lung cancer, staging provides a diagnosis of the severity or "stage" of a patient’s cancer without subjecting a patient to the trauma of exploratory surgery.
Nguyen believes the answers provided by staging can be a kindness to patients, even when they learn that their cancer is inoperable. "It relieves their anxiety in knowing the diagnosis. It expedites the patient to definitive therapy and avoids more imaging studies; they can bypass CT scans, bypass ultrasound. When we can tell them what stage their cancer is at, it can help them decide what route to take. Surgery? Surgery and chemo-radiation? Chemo-radiation only? To give them a diagnosis is to ease their worries."
The number of people for whom surgery would be a pointless ordeal is not inconsiderable; one study tracking surgery cases found that 33 percent of esophageal cancer cases and 75 percent of pancreatic cancer cases had been found inoperable. The money to be saved by eliminating surgery also is not inconsiderable. A Chang/Nguyen study of 37 patients with cancer of the esophagus found that for 17 of them, cancer had already progressed so far that surgery would be useless – producing savings from unnecessary surgery as well as recovery time.
The Gastroenterology division is also on the cutting edge in providing the newest treatment for the treatment of Gastroesophageal reflux disease (GERD). GERD can cause a wide range of symptoms, including persistent heartburn. More than 60 million Americans suffer from heartburn at least once a month and over 25 million suffer from it daily. Current treatment options include medications that neutralize the acid in the stomach and surgical procedures that tighten the esophageal sphincter. In fall 2001, Dr. Chang and his colleagues in GI offered two new options for the treatment of GERD: the Stretta Procedure and the Endoscopic suturing device, which offer patients suffering from GERD a less invasive outpatient procedure.
In addition to the two new treatments of GERD, the ingestable video capsule became available in fall 2001 for the diagnosis of small bowel disorders. Capsule Endoscopy provides quality images of the small bowel area through images captured in a small capsule, swallowed by the patient. The capsule acts as a digital camera as it travels through the patient. Images from the capsule are transmitted to a recorder which collects data that the physician later reviews.
In winter 2001, the Interventional Endoscopy Center and the Diagnostic Services Center will be breaking ground in the formation of the new Comprehensive Digestive Disease Center.
— Merrily Helgeson
Kenneth Chang, head of gastrointestinal oncology, holds a joint appointment in radiology. This merging of two disciplines probably has a lot to do with his interest in the synthesizing of existing technologies to create new diagnostic tools. The grafting of ultrasound to endoscopy created one promising technique – endoscopic ultrasound – but there are others.
Endoscopy joined to fluoroscopy – which is like a "real time" X-ray – offers a much easier way to implant a J-tube, or feeding tube, in patients. For one multiple sclerosis patient in early March, Chang used a "baby" scope – a miniature endoscope – to help guide a feeding tube past an obstruction in the small intestine. With the patient sedated on an X-ray table and a group of medical students observing, Chang manipulated the tiny endoscope against a background of fluoroscope-illuminated vertebrae, ribs and barely visible organs. The patient, a slender 50-year-old woman, had lost weight rapidly and developed SMA syndrome – her superior mesenteric artery, having lost cushioning fat, was pressing against the small intestine – and the only cure was to gain weight. In the past, this patient probably would have needed surgery to place the tube, but on this day she went home with a Band-Aid over a small abdominal incision.
Other hybrids will produce further advances, Chang believes. One of the newest is endoscopy joined to MRI, or magnetic resonance imaging. MRI works through a magnetic coil, Chang said; if that coil is miniaturized and placed at the end of an endoscope, a physician could image whatever is located near the coil.
By combining endoscopic ultrasound and fine-needle aspiration, Dr. Kenneth Chang can now visualize and biopsy tumors from within the body, offering patients earlier, more accurate cancer diagnoses and reduced pain and recovery time.