Ablation therapy is a type of minimally invasive surgery doctors use to destroy abnormal tissue that occurs with many conditions. For example, a doctor might offer it as an alternative treatment for kidney cancer patients whose cancer has spread to other tissue (metastatic). The goal is to remove as many cancer cells as possible. This therapy kills cancer cells by heating them (radiofrequency ablation) or freezing them (cryotherapy). It can be done with medicine that numbs the area to be treated (local anaesthesia) or that makes you sleep (general anaesthesia).