OBJECTIVETo analyze the major complications of percutaneous cooled-tip microwave ablation for the treatment of primary liver cancer and the possible risk factors of severe complications in a series of 693 patients.

METHODSThe clinicopathological data of 693 patients with primary liver cancer who underwent ultrasound-guided percutaneous cooled-tip microwave (MW) ablation in our hospital over the past 5 years were retrospectively analyzed, and the risk factors of severe complications were explored.

RESULTSIn a total of 693 patients with 898 primary liver tumors were treated and 1111 MW ablation sessions were performed. The mean diameter of tumors was (2.5 ± 1.2) cm and the range was 0.4 - 10.0 cm. Three deaths occurred in the peri-ablation period, including one case died of multiorgan failure, one case died of pulmonary embolism and one case died of hepatorenal syndrome. Major complications occurred in 27 (3.9%) patients, including 12 pleural effusion requiring thoracentesis (1.7%), 10 tumor seeding (1.4%), 3 liver abscess and empyema (0.4%), 1 hemorrhage requiring arterial embolization (0.1%), and 1 bile duct injury (0.1%). The Chi-square test results showed that the diameter of tumors, number of MW ablation sessions and histological type of tumor were significantly associated with the major complications rate (P < 0.05). The multiple variables 1ogistic regression analysis showed that only type of tumors was associated with the major complication rate (P < 0.05).

CONCLUSIONSResults of this study confirm that cooled-tip MW ablation is a relatively low-risk and effective minimally invasive procedure for the treatment of primary liver cancer. Proper direction for the treatment of cholangiocarcinoma (ICC) patients as well as fewer ablated tumor numbers during one hospital stay may help minimize the major complication rate in patients with primary liver cancer treated by ultrasound-guided percutaneous cooled-tip microwave ablation.