Risks of thermal ablation related to the anatomic location of the tumor
Superficial tumors adjacent to the gastrointestinal tract are at risk for thermal injury to the bowel wall. The colon appears to be at greater risk for perforation than the stomach and small bowel because of the thinner wall thickness and its lesser mobility. The gallbladder and biliary tract are also at risk for thermal injury. Perforation of the gallbladder is rare, but ablation of tumors adjacent to the gallbladder can be associated with iatrogenic cholecystitis, which is usually self-limited. Bilomas and biliary stenoses can also occur. Lesions in the dome of the liver can result in thermal injury to the diaphragm, pneumothorax, or hemothorax. Vessels in the vicinity or adjacent to lesions are usually protected because of the “heat or cold sink” effect of flowing blood. However, if the vessel is very small or the flow is decreased for any reason, thrombosis can occur. The heat or cold sink effect may also result in incomplete ablation of the neoplastic tissues adjacent to the vessel from temperature loss.