Injection of special chemicals into the tumor is called "chemical ablation" and the most commonly used chemical ablation method is alcohol ablation. In alcohol ablation, a thin needle is inserted into the tumor under local anesthesia and ultrasound or CT guidance. Alcohol is then injected into the tumor, which causes tissue death (necrosis) by disrupting the structure of the proteins (denaturation).
Alcohol ablation was first applied in 1980s to kill kidney tumors through the feeding vessels. Then, in the treatment of parathyroid and tiroid nodules, direct injection into the nodules was used and successful results were obtained. In the following years, alcohol ablation has been used successfully in liver tumors, especially in those called hepatocellular cancer (HCC). However, the use of radiofrequency and microwave ablation has reduced its popularity in the liver. Today, alcohol ablation is the standard treatment for cystic (fluid-filled) masses in all organs. For alcohol ablation, first a thin needle is placed into the cyst, the fluid is aspirated into the syringe and pure alcohol is injected into the cyst through the same needle. Alcohol will destroy the inner surface of the cyst, and thus, the cyst wall is shrunk and recurrence of the cyst is prevented.
Alcohol ablation is commonly used in cystic and semi-cystic lesions, especially in the thyroid gland. In contrast, it is used less frequently in solid tumors. However, it is still an important weapon in many cases because it is cheap, repeatable and can be performed with a very thin needle. Alcohol ablation can be extremely useful, especially when other ablation methods such as radiofrequency, microwave and cryoablation are not suitable or successful.