Destroying Kidney Tumors by Freezing Them

A relatively non-invasive technique that destroys kidney tumors by freezing them is a safe alternative to surgery, a new study has found.

Researchers at the Mayo Clinic (Rochester, MN, USA) treated 59 kidney tumors in 58 patients using percutaneous cryoablation. They found that the tumors were destroyed in 57 of the 59 cases. After an average follow-up of nine months for the 42 tumors that were available to the researchers, no tumor progression was found.

Percutaneous cryoablation is performed while the patient is under general anesthesia. Using real-time ultrasound for guidance, one or more cryoprobes are placed through the skin into the kidney tumor. The tumor is then frozen over the course of about 30 minutes. An unsuing ice-ball grows from the cryoprobes and envelops the tumor. The resulting freezing temperatures cause complete destruction of the tumor in over 95% of cases.

However, said the researchers, not all tumors are amenable to cryoablation, usually because the tumor lies too close to critical abdominal organs that could be injured by the ice-ball or because of the tumor's size. For this study, the researchers were able to treat tumors up to 7 cm in size. The study was presented at the annual meeting of the American Roentgen Ray Society in May 2006 in Vancouver (Canada).

"A relative drawback of surgery is its invasiveness, where a large incision or several smaller incisions are required. Recovery for surgery may be prolonged, on the order of weeks,” said Dr. Thomas Atwell, one of the authors of the study. "In contrast, percutaneous cryoablation is performed through small nicks in the skin, and the patient is dismissed from the hospital within 24 hours with a few Band-Aids.”



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