Memphis now boasts one of the newest advances in the field of tumor ablation, utilizing microwave technology. The West Clinic announced last month it would offer microwave ablation as a treatment option for patients with inoperable liver, lung and kidney tumors.

 

"The FDA approved this technology last year and we were the first to use it in Tennessee," said Tom Hodgkiss, MD, interventional radiologist at The West Clinic. "Then insurance would not pay for it, because at the time they termed it investigational. In the hospitals you could probably absorb that, but in the clinic we couldn't. We found out recently they were going to reimburse, and we're able to do them again."

 

For the last 10 years, Hodgkiss, who is board-certified in radiology and fellowship-trained in interventional radiology, has done hundreds of radio frequency ablations (RFA). In RFA, a consciously sedated patient is entered with a CT-guided needle to reach the center of a tumor. Radio waves heat the needle to destroy the malignancy. In microwave ablation, the same process is used, but microwave energy emanates from the feed point of the antenna. The system creates heat by generating friction through vibration of water molecules and induces cellular death by coagulation necrosis. After a focused effort to get the needle in the perfect spot (which could take up to 15 minutes) the microwave process itself takes 10 minutes.

 

The technology has allowed Hodgkiss to accomplish more with certain types of malignancies, such as lung cancer. Lung tumors pose special problems for RFAs, because as the patient breathes during the procedure, the needle cools. This is not a problem with microwave energy. This year, a study of The Journal of the Radiological Society of North America concluded microwave ablation is a more effective treatment for lung tumors, because it creates larger and more circular zones of ablation than other methods.

 

"The great thing about the procedure is how well patients tolerate it. Most patients can go home by noon the morning of the ablation. They will describe soreness in the area for about a week and then it goes away. It's definitely another weapon in the arsenal," Hodgkiss said.

 

Hodgkiss explained this weapon has worked extremely well in conjunction with other therapies. Where stereotactic radiation is excellent at killing tumors on the edges, microwave technology is very good killing tissues in the center of the lesion. If there is a liver tumor too big for ablation, Hodgkiss will use chemoembolization, a method of implanting tiny, chemotherapy-filled beads into vessels supplying the tumor with blood. The beads roll out until the blood vessel is completely occluded, cutting off the tumor's blood supply. Then, the beads will drip chemotherapy, ten times the usual concentration, directly to the tumor for two weeks.

 

"Due to the chemoembolization, I've got the tumor starved now and then it is getting concentrated chemotherapy. I can come back with a bigger burn with the microwave ablation, because the tumor doesn't have the blood supply and you can get a higher temperature and hit a bigger area," he said.

 

Microwave is also very consistent about heating. Where a 3 cm spherical tumor might have had a small untreated area resulting in residual tumor requiring treatment two or three months later, that is not the case with the new technology. An organ where microwave ablation excels is the liver. As tumors blend in with surrounding tissue, it is difficult to target lesions, but the new technology is better at getting it all the first time.

 

"We probably did 75 radio frequency ablations last year and four microwave," Hodgkiss said. "Most likely half of those will be replaced with microwave this year."

 

He recounted the case where a 65-year-old woman with retinal ocular melanoma endured treatment and then the cancer found her liver. In her case, interleukin was indicated, but she could not tolerate it. It took him three ablations to get all the tumors out of her liver. Then, the cancer returned in a lung. He treated that, and then a lesion appeared on her thigh. He treated that and now it has metastasized to her brain. Her brain tumor is operable, and she is scheduled for surgery.

 

"In the course of a couple or three years, I have done RF or microwave on her six times and in all those spots, the tumor is gone. I call her the cat with nine lives. Our patients are just amazing," he said.

 

Then there was the man who came down from Indiana with a history of pancreatic cancer and a solitary metastasis in his liver. He had been told with chemotherapy he would have a year to live. Without it, he'd have six months. After reviewing his case and his films, Hodgkiss told him he could treat it.