SIR 2009: Percutaneous Cryoablation May Be New Standard of Care for Small Renal Tumors

Roxanne Nelson

March 11, 2009

March 11, 2009 (San Diego, California) — Interventional cryoablation is an effective treatment for small renal tumors, and should be the gold standard or first treatment option for all patients with lesions that are 4 cm in size or smaller, researchers say.

It might also be a viable option for larger tumors, up to about 7 cm in size, for patients who wish to avoid or cannot have surgery, according to a study presented here at the Society of Interventional Radiology (SIR) 34th Annual Scientific Meeting.

"These new types of procedures are game changers, and they change the way we think," said Brian Stainken, MD, president-elect of SIR, who was not involved in the study. "But it is important to know that we have good data before we offer game-changing solutions."

Based on a preponderance of data, this technique is ready to be used in general clinical practice, he told Medscape Oncology in an interview. "More than three quarters of individuals with kidney cancer have tumors that are 4 cm or less in size," he said. "For patients with small tumors, this procedure can take the place of removing the entire kidney. It can replace having to undergo significant surgery, and might even be possible to conduct on an outpatient basis."

In this study, Christos Georgiades, MD, PhD, from the Division of Vascular & Interventional Radiology at Johns Hopkins Hospital, in Baltimore, Maryland, presented efficacy data from 90 cryoablation procedures that were performed on 84 patients with renal tumors ranging in size from 1 to 10 cm. The procedures were conducted at Johns Hopkins Hospital from April 2006 through December 2008, and patients were followed every 3 months during the first year, and annually thereafter.

Usage Varies Among Facilities

At last year's SIR meeting, Dr. Georgiades presented preliminary data from the study, which was reported by Medscape Oncology. At that time, Dr. Georgiades said that he initially performed cryoablation on patients who could not undergo surgery because of comorbidities, but now offers the procedure as an alternative to patients who can undergo surgery.

Stephen Solomon, MD, a cryoablation specialist from Memorial Sloan-Kettering Cancer Center, in New York City, spoke with Medscape Oncology last year. Cryoablation was "still relatively far from becoming the standard of care," he said, and "many surgeons still prefer to cut out the tumor."

Dr. Solomon, who was not involved in the study, also told Medscape Oncology that the proportion of kidney tumors treated with cryoablation varies among institutions; some do not use it at all, whereas others treat 15% of tumors smaller than 4 cm with this method. The technology is widely available, with 2 companies involved (Endocare and Galil), and the market is growing, he said.

At this year's presentation, Dr. Georgiades reported that interventional cryoablation has now become the first-line treatment for small tumors at Hopkins.

Small Tumors Had 100% Response

Dr. Georgiades noted that they didn't initially set a threshold of 4 cm or less as the optimal size for the procedure. "We have treated patients with tumors up to 10 cm — admittedly, these are patients who could not have surgery for whatever reason," he said during a press briefing. "But we found that patients with tumors that were 4 cm or smaller were the ones with a 100% response, so that's why our recommendation stops at 4 cm."

"We have had equally good results with lesions up to 7 cm, but we've only treated between 5 and 10 patients with lesions that size, so I cannot make a generalized conclusion for larger tumors," he added.

Within this cohort, 88 tumors were treated completely, without any evidence of cancer remaining. Two patients had a small amount of residual disease (~1 cm), and 1 patient was retreated with a complete response. The other patient refused further treatment.

Follow-up data are available in a subgroup of patients for 2.5 years, explained Dr. Georgiades. "Efficacy is still 100% and none have shown any local tumor recurrence or metastatic disease," he said.

There are major advantages to percutaneous cryoablation, compared with other procedures. "There is no surgery, no incision, and no general anesthesia," Dr. Georgiades explained. "There is some pain when the tumor begins to thaw, and some inflammation, but we can easily address that."

Most patients go home the same day or the following morning, he added. Compared with surgery, there are also fewer complications and lower cost. "In the unlikely case that cryoablation fails, the patient can still undergo surgery," he said.

Strong Safety Profile Reported

In a related safety study, Dr. Georgiades evaluated the results of 81 computed tomography (CT)-guided percutaneous cryoablations conducted in 73 patients who either couldn't undergo surgery or who elected to undergo the interventional radiology treatment. Patients were followed in the clinic at 3, 6, and 12 months, and annually thereafter.

The lesions ranged in size from 1 to 10 cm, and 13 (16%) were benign. All peri-procedural and long-term complications were categorized according to the Common Terminology Criteria for Adverse Events (CTCAE).

Overall, the researchers found that CT-guided percutaneous cryoablation had an "excellent safety profile." They observed a total of 6 (7.4%) CTCAE category >1 complications, including cryoshock, bleeding, pleural effusion, pneumothorax, and fistula. In addition, 22 (27%) self-limiting CTCAE category 1 events were noted; there were no procedure-related deaths.

"There is always going to be a role for more aggressive and conventional therapies," said Dr. Stainken. "What we need to do now is sort out when minimal is best and when conventional is best. But all of these choices need to be available to patients."

Dr. Georgiades has disclosed no relevant financial relationships.

Society of Interventional Radiology (SIR) 34th Annual Scientific Meeting: Abstracts 18 and 19. Presented March 9, 2009.

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