Mission



Turning Up the Heat
on Liver Tumors

ablation

by Will Sansom

It sounds futuristic--burning away a liver tumor in one outpatient treatment. People are used to the idea of a dermatologist removing a mole during a clinic visit, but removing a tumor from the liver, without major surgery? Yet it's happening right now--a Health Science Center physician is removing liver tumors in the morning, and the patients are going home by the afternoon. They even feel like sitting up and eating something in between.

The new procedure is called radiofrequency (RF) thermal ablation, and Gerald D. Dodd, III, M.D., a Health Science Center radiologist, has performed more of the liver-burning procedures than almost anyone in the country. More than half the liver tumors "ablated" by Dr. Dodd have not recurred--an impressive figure considering the poor response of these tumors to conventional forms of therapy. Dr. Dodd is a professor in the Department of Radiology and a staff physician with two of the Health Science Center's teaching partners, University Hospital and the South Texas Veterans Health Care System.

Dr. Gerald Dodd


Setsuko Bass, a 64-year-old San Antonio businesswoman, tells everyone about RF thermal ablation. She is a survivor of liver and colon cancer; her tumors had spread, or metastasized, to the liver from the colon. In June 1997 she underwent surgery to remove a large part of her colon. "At that time the doctors knew something [cancer] was in my liver, too," she said. "They did a biopsy and found 75 percent of it was affected. They could not do surgery. They closed me up, and I had to take chemotherapy. I was dead, believe me, I was dead. The doctors expected me to live only three to five months."

Bass withstood the exhausting chemotherapy regimen through the summer and early fall that year. A manager with Hayakawa Sanki Inc., a Tokyo-based company that makes soft drink dispensers, she even went to Italy for a purchasing show. In the meantime her surgeon, Peter W. Hollimon, M.D., suggested she meet Dr. Dodd and hear about RF thermal ablation. Encouragingly, the chemotherapy had shrunk her liver tumors more than 50 percent, making her an excellent candidate for thermal ablation. "I thought about it two days, then said: ‘Yes, I'm going to see Dr. Dodd.'"

A sonogram at University Hospital revealed two spots on Bass' liver. Though it was clear the chemotherapy had been effective, the cancer needed to be completely eradicated for her long-term survival. RF thermal ablation was an option because enough healthy liver tissue remained around her liver tumors. Dr. Dodd informed Bass that she was a good candidate to join the Health Science Center's clinical trial, and that she could become only the 40th patient in Texas to undergo the procedure. "I said yes," she recalled. "What did I have to lose? Now I'm still alive, and my doctors call me a miracle child." Indeed, CT scans in 1998 and early 1999 revealed no tumors in her liver, and blood tests for cancer cells have proved negative.

Dr. Dodd has performed RF thermal ablation on more than 75 patients with liver carcinoma and killed all tumors the first time out in about half of the patients. Other patients required subsequent ablations for recurrent tumors. "We have killed 65 percent of treated tumors, a much higher percentage of success than has been shown with chemotherapy and radiation," he said. "The fact we have obliterated almost two-thirds of tumors in these 75 patients represents a major victory."


Bass

Bass is living life after cancer with considerable energy and zeal. She runs her own travel business and serves as office manager for Hayakawa Sanki's busy San Antonio office. A self-described dynamo who "can't keep still," she's on the go day and night and travels around the world every few months. In April she visited Tokyo for three weeks on business. "You have to fight; you can't cry," she said.

"Each year about 100,000 people in the United States, like Ms. Bass, develop primary or secondary malignant liver tumors," Dr. Dodd said. "Traditional cancer therapies such as chemotherapy or radiation are ineffective in the treatment of these tumors. Surgical resection of the tumors is considered the only potentially curative therapy for these patients. Unfortunately, few patients are surgical candidates and of those who undergo surgery, 50 percent to 60 percent develop new liver tumors within one to five years.

"We need a new form of therapy that is minimally invasive, causes few side effects, and can be used repeatedly as necessary to treat recurrent tumors," Dr. Dodd added. "RF thermal ablation meets those requirements. It is anticipated that with ongoing refinements in this technology, it may soon become the treatment of choice for patients with liver tumors." Dr. Dodd recently presented the technique at the largest radiology meeting in the world, the annual conference of the Radiologic Society of North America.

Scientists this decade have developed several minimally invasive techniques to
treat liver tumors. These include cryotherapy (freezing), alcohol injection therapy, and
laser, microwave and radiofrequency heat ablation. "Of these, RF thermal ablation appears to be the most promising," Dr. Dodd said. "The treatment involves placing a needle through the skin and into a liver tumor. The needle is a special electrode through which a radiofrequency current is passed. The radiofrequency current heats the tumor around the tip of the needle and kills the tumor by cooking it. The procedure causes only minimal discomfort and can be performed without a general anesthetic."

Because healthy tissue can withstand greater heat than a liver tumor, physicians using RF thermal ablation are able to destroy a tumor and a small rim of tissue around its edges without affecting healthy liver tissue. The procedure requires an abdominal incision about 5 millimeters wide to accommodate entry of the needle. Patients usually are cleared to leave the hospital just a few hours after treatment.

Since Bass' procedure, another 35 patients have undergone one or more sessions of RF thermal ablation with Dr. Dodd. Of the first 75 patients treated in San Antonio, only one suffered a complication and many are tumor-free after their latest check-ups. Without treatment, they could have expected to live six to 12 months. Even after traditional surgical resection of liver tumors, only 30 percent of patients survive more than five years. "But RF thermal ablation currently is used only in patients for whom surgery is not an option," Dr. Dodd said. "For now, surgery is the treatment of choice."

RF thermal ablation must be further proven, agreed Bradford J. Wood, M.D., who, like Dr. Dodd, studies thermal ablation. Dr. Wood is an assistant professor in the Division of Interventional Radiology at the Georgetown University Health Science Center and a staff clinician in the Special Procedures Division, Department of Radiology, at the National Institutes of Health. "RF thermal ablation will be more widely available in the future--the initial, preliminary results certainly look good," Dr. Wood said. "But they are preliminary; there has been no randomized, prospective clinical trial of RF thermal ablation, and no long-term follow-up with patients. But intermediate and short-term follow-up data look very promising, mostly in the treatment of primary and metastatic liver tumors."

tumors1-3 tumors1-3 tumors1-3

The NIH radiologist met Dr. Dodd in Boston a couple of years ago, when Dr. Dodd gave an invited lecture at Massachusetts General Hospital. "Dr. Dodd is certainly a well-respected researcher in this field, and continues to make a profound contribution in ultrasound-guided intervention," Dr. Wood said. "He undoubtedly will help us to determine the exact role that RF thermal ablation will play in oncologic [cancer] care."

Dr. Dodd, along with David L. Shepherd, M.D., assistant professor of surgery in the Health Science Center's Division of Urology, plans to do a research study of RF thermal ablation in patients with small renal cell (kidney) carcinoma. Like the liver, the kidney is a large organ with healthy tissue surrounding most tumors. Today, surgeons generally remove the kidney and stop the cancer threat in nearly all patients with small renal cell carcinoma. "We want to study thermal ablation in patients who are going to have a kidney removed for renal cell carcinoma," Dr. Dodd said. "Since removal of a kidney is so effective at stopping renal cancer, we cannot suggest thermal ablation as an alternative to surgery until we see a 100 percent kill rate of tumors, by ablation, in these patients. But obviously, a viable alternative to losing a kidney is well worth exploring."

RF thermal ablation caught Dr. Dodd's interest several years ago. He first used the technique to ablate liver tumors in 1996, in collaboration with Glenn A. Halff, M.D., associate professor of surgery and director of organ transplantation programs at the Health Science Center. Most of Dr. Dodd's patients have been adults, but he has treated two teenagers, including one adolescent diagnosed with a gastric sarcoma, or cancer of the stomach, that had spread to the liver. The technique is only performed after cancer in other sites has been effectively treated with surgery and/or chemotherapy and radiation.

Manufacturers have introduced several models of the ablation equipment, including the generator supplying radiofrequency current to the heated needle. Previous models could eliminate tumors of 2.5 to 3 centimeters (about 1 inch) in diameter, but Dr. Dodd's team is using a new-generation needle that can destroy tumors up to 4 to 5 centimeters (almost 2 inches) in diameter. "Our ability to treat larger tumors is improving," he said. (See series of three illustrations above.)

tumors1-3 tumors1-3

RF thermal ablation of liver tumors was proposed as early as 1990 in the United States and Italy, and the Italian doctors were the first to treat liver cancer patients with the technique. Four major centers did the bulk of the clinical work in this country. The Health Science Center and Massachusetts General Hospital were the two primary U.S. centers to study liver tumor ablation as a minimally invasive, outpatient procedure. The University of California, San Francisco and the U. T. M. D. Anderson Cancer Center in Houston have studied it from a surgical, inpatient perspective.

The U.S. Food and Drug Administration is compiling data on RF thermal ablation as a treatment for liver cancer and may give its stamp of approval in the near future. For now its application in the area is considered experimental. The technique long has been approved for other applications, such as cardiac ablation to correct abnormal heart rhythms and neural ablation to relieve debilitating pain.

South Texas' first clinical trial of liver tumor ablation enrolled 46 patients at University Hospital and the Audie Murphy Hospital Division of the South Texas Veterans Health Care System. Since the end of that first study, Dr. Dodd and his colleagues have continued to see patients. "We still don't have much scientific data, certainly not enough to make sweeping assertions about RF thermal ablation, but even from our first 75 patients we can see it holds great promise," he said. "Its ultimate role in treating liver cancer is yet to be decided, however."

Setsuko Bass isn't interested in such things. All she knows is that RF thermal ablation was there for her when she needed it. Jetting around the world, she has a second chance to live. "The doctor can never find me," she said. "I want to tell all the cancer patients: 'Be strong! Look at me--it's been a year and three months since my first treatment. You have to believe in it and have the will to fight. And I'm still fighting.'"


Arrow Viewing the operation


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