Source: Diabetologia  |  Posted 5 years ago

By Ed Susman

CHICAGO, IL -- December 4, 2006 -- Cryoablation or renal tumors -- some as large as 7 cm in diameter -- can be accomplished safely and with excellent control of local recurrence up to 27 months, researchers demonstrated here at the 92[^]nd[] scientific assembly and annual meeting of the Radiological Society of North America (RSNA).

"Percutaneous cryoablation of these large renal tumors are technically feasible, relatively safe and are a reasonable alternative to radiofrequency ablation," said Thomas Atwell, MD, instructor of radiology, Mayo Clinic School of Medicine, Rochester, Minnesota.

Radiofrequency ablation of renal cancers has had shortcomings, especially when attempts are made to destroy tumors larger than 3 cm in diameter. Dr. Atwell and colleagues expected that with cryoablation -- where the iceball created can be visualized on computed tomography [CT] -- they might be able to control these tumors in percutaneous procedures, he said in an oral presentation on November 26[^]th[].

In the retrospective analysis, the researchers identified 44 patients with 44 tumors treated at their center since April 2003 with cryoablation techniques. Tumors were larger than 3 cm (average size 4.2 cm; range 3.0-7.2 cm). The majority of patients study were men, and the mean age was 75 years.

Patients were placed under general anesthesia and the cryoprobes were inserted into the tumor using ultrasound guidance. The iceball that develop and encompassed the tumor was monitored by CT, Dr. Atwell said.

He illustrated one procedure in which 6 probes were inserted into a 6.7 cm tumor. "Over the course of 20 to 25 minutes, the tumor was frozen and could be observed coalescing into an iceball," Dr. Atwell said. The procedure can cause some clinically insignificant hemorrhage at the ablation site, he added. After 15-months of follow up in this particular patient, the tumor had decreased in size and no local recurrence has appeared.

"We had 2 technical failures over the course of treatment of the 44 tumors. Both of the tumors we failed to treat in the central margin of the tumor where it extends into the central part of the kidney," he said.

In 1 case, a grade III hemorrhage occurred, requiring interventional radiology support and blood transfusion. It occurred as doctors attempted to ablate the largest tumor in the series. The single major complication reflects a 2% complication rate. About 25% of patients developed hematoma, but they resolved without additional treatment.

After an average follow-up of 11 months, no tumor recurrences have been observed. However, Dr. Atwell said that renal cell carcinoma is generally slow growing, so the failure to see any recurrence in the current time frame is not remarkable.

[Presentation title: Percutaneous Cryoablation of Renal Tumors 3.0cm or Greater in Size: Technical Success and Short-term Outcomes. Abstract SSA02-03]