Cancer is the second cause of death in the developed world with 2, 645, 000 estimated deaths/year. Due to the wide variety of cancer types, stages and locations, there is no unified approach to treatment. Cancer therapy still relies on a wide variety of techniques. Traditional treatment options are surgery, radiation therapy and chemotherapy. New treatment approaches based on local tumor ablation have lately received much attention from the medical community.

Tumor ablation

 Ablation techniques rely on the principle that the tumor is not removed (like in a surgical resection) but rather destroyed in place. The necrotic tumor is then disposed off by the body immune system, leaving only some scar tissue.

Several ablation methods have been developed, differing in the means to destroy the tumorous cells. The most widely used ablation methods are:

• Arterial embolization : the blood supply to the tumor is blocked by means of small particles injected into the artery feeding the cancerous organ.
• Chemical ablation: the tumor is destroyed by a local ethanol injection into the tumor tissue.
• Thermal ablation: the targeted tumorous tissue is destroyed by a local temperature increase above a lethal treshold (>50°C).
• Cryoablation: tumorous cells are destroyed by repeated freezing – thawing cycles

Minimally invasive therapies

 A common trait of these ablation therapies is the limited invasiveness of the procedure hence their qualification as « minimally invasive ». Indeed, most ablation therapies rely on the insertion of a needle-like applicator into the body either through the skin (percutaneous) or through a vessel (intra vascular) resulting in a very well tolerated intervention, often performed on an outpatient basis.

RF ablation of a liver tumor. The needle (right) is inserted in the tumor (center). The tumor is effectively destroyed after a 25 min procedure leaving only a small needle puncture hole (right), hence the terms minimally invasive therapy (images courtesy of Dr. Palussière, Institut Bergonié, Bordeaux).

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