Technique Shows Promise Against Small Kidney Tumors

By Rachael Myers Lowe, cancerpage.com

(January 28, 2003) - New minimally invasive technique shows promise for removing small Stage I kidney tumors that can"t for one reason or another be removed through traditional surgery.

Doctors at Massachusetts General Hospital have pioneered a technique using Radio Frequency Ablation (RFA) against non-operable kidney tumors. They report their findings in the February issue of Radiology.

RFA works by delivering to the tumor intense heat generated by electricity at the end of a thin probe. The surgeon guides the probe to the tumor site with a CT scan, ultrasound, or some other imagery technique. In many cases, RFA can be performed on an outpatient basis as opposed to traditional surgery, which usually requires admission to the hospital.

While surgery is considered the standard of care for early stage kidney cancer, it is not appropriate for all patients. Patients with only one kidney, who have reduced kidney function, or some other medical condition making surgery risky, such as advanced age, may not be good surgery candidates. So the use of RFA offers a treatment option other than just waiting to see what happens.

Doctors at Massachusetts General Hospital have been following the progress of 34 patients treated with RFA for three and a half years in one of the largest studies of its kind.

A total of 42 individual tumors ranging in size from 1-9 cm were treated with varying results. (In the average adult, a kidney is about 9-10 cm long.)

The researchers report all the tumors located on the surface of a kidney were completely destroyed regardless of tumor size. Tumors located inside the kidney proved more difficult to treat although more than half of them were also totally destroyed with more than one treatment.

In an interview with cancerpage.com, the study"s lead author, Debra Gervais, MD, assistant professor of radiology at Harvard University and director of abdominal intervention at Massachusetts General Hospital, said no tumors larger than 5.5 cm were completely destroyed. The surface tumors were easier to treat, she said, because the RFA was able to deliver higher temperatures to the target tumor.  Larger tumors in the core of the kidney proved more difficult because blood vessels continued to bath the tumors in body temperature fluid, thus lowering the temperature RFA could achieve.

Gervais says since the Radiology paper was written and submitted for publication 28 more patients have been treated and are being following for long-term survival.

During the follow-up period of the initial study, 30 patients had no local recurrence of the treated tumor. Four patients died of unrelated causes, two had no local tumor recurrence.

According to the American Cancer Society, nearly 32,000 American will be diagnosed with kidney cancer this year. Gervais says only a small subset of patients are diagnosed with early stage tumors appropriate for the RFA procedure but that number is likely to grow.

"It turns out that more and more patients are having their renal tumors diagnosed while they are still small because they"re being picked up almost incidentally. almost by accident because a patient gets a CT scan or ultra sound for some other reason and our population is aging, so as time goes on there will probably be more patients that fall into this category," Gervais said.

RFA has been used for several years against inoperable liver tumors and as a treatment of a rare benign bone tumor, osteoid osteoma. The FDA has approved the technique for relieving intractable bone pain caused by cancer"s spread.

SOURCES:

• Radiology February 2003; 417-424
• cancerpage.com interview with Dr. Debra Gervais on 1-27-03
• Procedure Offers Relief of Intractable Bone Pain, cancerpage news story 10-31-02