DALLAS (The Fort Worth Star-Telegram) - Three hours after a cancerous tumor was removed from his kidney, David Rist drove himself home from the hospital.

"I never had any pain, never had to take even an aspirin," said the retired Delta Air Lines pilot and father of four.

"The next day, I cut the grass."

Rist has been cancer-free and going strong ever since the procedure Aug. 17. A new twist on an old technique - using heat instead of a knife - made it possible. It's called radiofrequency ablation, and it's one of the latest tools in the cancer-fighting arsenal.

"It sounds almost too good to be true," said Rist's physician, Dr. Jeffrey Cadeddu, an assistant professor of urology at the University of Texas Southwestern Medical Center at Dallas. "Especially when the alternative treatment is open surgery with an incision around the side or across the abdomen."

UT Southwestern is one of the first institutions nationwide to use radiofrequency ablation, or RFA, on kidney tumors. Although the treatment is still being tested on different types of cancer, early results are promising and suggest that RFA provides safe and effective local treatment of some cancers, according to the National Institutes of Health.

During the procedure, a needle is inserted through the skin into the kidney. Once inside the body, the probe opens up, much like an umbrella, then wraps around the tumor. Reaching a temperature of 105 degrees Celsius - above boiling - the heat kills the tumor within five to seven minutes. "It's like barbecuing it," Cadeddu said. "It cooks it from the inside out."

When the procedure is finished, a hard, dead piece of tissue remains. Over time the dead tissue shrinks and turns into a scar, Cadeddu said.

For Rist, the procedure could mark the end of a medical ordeal that began in August 2000, when he was diagnosed with tumors in both kidneys.

Although he had no obvious symptoms, he was troubled by a pain in his back. At first he attributed it to an injury he suffered six months earlier when he fell from a tree and cracked his ribs.

But the pain would not go away. He asked his doctor to do further tests, and that's when two growths - one a tumor bigger than a kidney - were discovered.

Surgery was his only option. But the four-hour operation to remove the kidney with the larger tumor left Rist with a 22-inch scar that started at his rib cage and stretched around his back. Recovery was long and painful.

With only one kidney left, Rist decided to take a wait-and-see approach to treating the other, much smaller tumor. The American Cancer Society estimates that there will be about 30,800 new cases of kidney cancer this year. In about 50 percent of the cases, the cancer has not spread outside the kidney when discovered. Most renal cell carcinomas occur in adults between the ages of 50 and 70.

In Rist's case, the large tumor probably had been growing for four to five years.

Although the remaining mass was not growing, knowing it was there was agonizing for the Rists, who live in Richardson.

"It was just a worry all the time," said Rist's wife, Mary. "One day we would think it might be just a cyst, then the next minute we were thinking, what if it is cancer, and while we were waiting it was spreading."

When the Rists discovered RFA through the Internet and other sources, they were convinced it was the answer. "I felt all along very upbeat, because I knew the only way to solve the problem was to get in and get the tumor out," Rist said. "The first surgery was such a monster. But I looked forward to this one in a way, because it seemed to be smart way to do it."

The procedure is not for everyone. Only tumors smaller than a golf ball can be removed this way, Cadeddu said. In some cases, such as when the tumor is in the central part of the kidney, there can be complications such as bleeding. Early studies suggest RFA provides safe and effective local treatment for some cancers, including liver and lung tumors, according to the National Institutes of Health.

Rist's treatment, which was performed at Zale Lipshy University Hospital in Dallas, proved to be easier than he imagined.

After being lightly sedated, Rist underwent the procedure, then was taken to recovery. He experienced no pain and wanted to leave the hospital before the doctors were willing to release him.

A month later, a scan showed no sign of disease. Rist's health will be frequently monitored to make sure there is no more cancer.

Since the procedure is new, there's no long-term data to prove it is equivalent to standard therapy, Cadeddu said. "The downside is we do not know long-term whether this technology is equivalent to surgery," Cadeddu said. "We think it is."

The five-year survival rate is about 60 percent for all people diagnosed with renal cell carcinoma, according to the American Cancer Society. Patients who have a small tumor that has not spread have an 82 percent chance of a cure. Rist is confident it was the best choice he could have made. He has about a 30 percent chance of the cancer reoccurring during his lifetime, he said. If a small tumor develops, Rist could undergo the procedure again. For now, the Rists are busy planning for the retirement lake home they put on hold when he was diagnosed with cancer.

"This procedure was almost like a miracle to us," Rist said. "We feel very fortunate."

Copyright 2001 The Fort Worth Star-Telegram. All rights reserved.