Cancer Treatment Today

Standard approach to kidney cancers is surgical resection, usually a complete nephrectomy, although partial nephrectomies are sometimes done when sparing renal function is imperative. Small renal masses have recently been treated by cryoablation (freezing to at least -19.4 °C using liquid nitrogen or argon). In cryoablation, a small freezing probe is insertead through the skin, and its tip is placed into the cancerous tissue using CT and ultrasound guidance. Retrospective studies suggest an around 95% success rate. Subsequent MRI or CT scans are used to evaluate the ablation, with diminution of the tumor in the cryolesion and lack of contrast enhancement considered a favorable result, and increase of the tumor in the cryolesion or interval growth considered signs of inadequate treatment. A percutaneous biopsy, a standard resection, or retreatment with cryoablation can then occur. The mechanism leading to tumor destruction is uncertain and may be a combination of direct cytotoxicity and damage to vascular elements leading to ischemic necrosis. The cryoablation studies carried out to date fail to convince that a potentially malignant renal mass has been eradicated. The uncertain biopsy data before and after ablation, short follow-up, and requirements for lengthy general anesthesia and frequently for laparoscopic surgical intervention, weaken the argument for renal cryoablation as a paradigm shift. The U.S. Food and Drug Administration approved this treatment for kidney cancer, but research studies still need to measure long-term outcomes to compare cryoablation to other treatments.Kaouk JH, Aron M, Rewcastle JC, Gill IS. Cryotherapy: clinical end points and their experimental foundations. Urology 2006;68(1 suppl):38–44.[Paul Russo Renal cryoablation: a new treatment in need of careful clinical investigation Nature Clinical Practice Oncology (2006) 3, 286-287