The electrodes are inserted into the liver tumor under ultrasound image guidance using percutaneous, laparoscopic or open surgical approach. It is suitable for small tumors (<5 cm). RFA has the best outcomes in patients with a solitary tumor less than 4 cm. Since it is a local treatment and has minimal effect on normal healthy tissue, it can be repeated multiple times. Survival is better for those with smaller tumors. In one study, In one series of 302 patients, the three-year survival rates for lesions >5 cm, 2.1 to 5 cm, and ≤2 cm were 59, 74, and 91%, respectively. A large randomized trial comparing surgical resection and RFA for small HCC showed similar four-year survival and less morbidities for patients treated with RFA. Cryoablation is a technique used to destroy tissue using cold temperature. The tumor is not removed and the destroyed cancer is left to be reabsorbed by the body. Initial results in properly selected patients with unresectable liver tumors are equivalent to those of resection. Cryosurgery involves the placement of a stainless steel probe into the center of the tumor. Liquid nitrogen is circulated through the end of this device. The tumor and a half inch margin of normal liver are frozen to −190 °C for 15 minutes, which is lethal to all tissues. The area is thawed for 10 minutes and then refrozen to −190 °C for another 15 minutes. After the tumor has thawed, the probe is removed, bleeding is controlled, and the procedure is complete.
Benign hypertension or benign essential hypertension are historical terms that are considered misleading, as hypertension is never benign, and consequently they have fallen out of use (see history of hypertension). The terminology persisted in the International Classification of Disease (ICD9), but is not included in the current ICD10. == References ==