IMAGE-GUIDED CRYOABLATION

RENAL TUMOR — Cryosurgery Procedures

Image-Guided Kidney Cryoablation – How Successful is it
Determining the “success rate” of any given medical treatment can be difficult, especially when discussing a fairly recent treatment innovation. There are many reasons for this. Many new treatments are first used on patients who have had other treatments fail, or who, because of their poor health, are not candidates for traditional treatment. Also, these new treatments are often used in cases where the hoped for result is palliative rather than curative. Image-guided kidney cryotherapy is no exception.

There are many patient series reported in the literature, and it is important to understand the criteria that each uses to determine “success.” Additionally, most current published results are for patients with “short-term” and “mid-term” follow-up; because the treatment is new, “long-term” follow-up results are not available on a wide population of patients.

A recent study by researchers from the Mayo Clinic in Rochester, MN, found that percutaneous cryoablation is a safe method for treating kidney tumors in selected patients who are not considered candidates for surgery.

“We can literally watch the evolving iceball grow from the cryoprobes and encompass the tumor,” said Dr. Thomas Atwell, one of the authors of the study. “The freezing temperatures destroy the tumor cells and, based on short-term follow-up, results in complete destruction of the tumor in over 95% of cases.”

In the July, 2007 Issue of Cancer Control, J. Hafron MD and J Kaouk MD authored “Cryosurgical Ablation of Renal Cell Carcinoma”, a retrospective study of six of the largest published series of renal cryoablation with a total of 320 patients. The results and conclusions of this study were as follows:

Results:
Renal Cryoablation for localized small renal masses is well-tolerated and associated with a low complication rate. The range of mean tumor size…was 2.3 to 2.6 cm. After a range of mean follow-up of 5.9 to 72 months, including a series with a minimum of 5 years follow-up, the cancer-specific survival was 97% to 100% and overall patient survival was 82% to 90.2%.

Conclusions:
Renal cryoablation, based on available clinical reports, appears to be a curative option for patients with small localized renal cell carcinomas (RCC’s) who are unwilling or unable to undergo a partial nephrectomy. With encouraging intermediate oncological follow-up available, longer-term follow-up is needed to validate the use of cryoablation as a primary treatment option.

With intermediate results being very encouraging, long-term study results are being anxiously awaited in hopes that soon more physicians and patients can benefit from the known advantages of this minimally invasive kidney cancer treatment.