Microwave ablation vs. cryoablation for treatment of primary and metastatic pulmonary malignant tumors

At present, minimally invasive surgery is one of the primary strategies for the treatment of malignant pulmonary tumors. Although, there are some comparative studies between microwave ablation and radiofrequency for the treatment of malignant pulmonary tumors, there are few studies that have investigated the comparison between microwave ablation and cryoablation. The aim of the study was to retrospectively compare the efficacy and complications of microwave ablation (MWA) and cryoablation in the treatment of malignant pulmonary tumors. A retrospective analysis was performed on 48 patients with malignant lung tumors treated with MWA or cryoablation in The Third Hospital of Mianyang and The Affiliated Hospital of North Sichuan Medical College between June 2014 and June 2018. Of these patients, 29 received MWA and 19 received cryoablation. Intraprocedural pain was evaluated by using the visual analog scale (VAS). The intraprocedural pain, response rates, overall survival (OS) and complications rates were compared between the MWA group and cryoablation group. The results showed that the patients in the MWA group experienced more pain than those in cryoablation group as the MWA group VAS scores were much higher than those in cryoablation group (P<0.001). The overall response rate of the MWA group [21/29 (72.41%)] was not significantly different from the cryoablation group [14/19 (73.68%)] (P=0.92). The 6-, 12-, 24- and 36-month OS rates in the MWA group and cryoablation group were 92.72, 81.28, 64.54 and 54.91%, and 94.07, 81.13, 57.33 and 43.04%, respectively. No significant differences were found in the OS rate between the two groups (P=0.79). The complication rates in the MWA and cryoablation groups were 34.48 and 36.84%, respectively; there was no significant difference between the two groups (P=0.59). No patients died during the perioperative period. Cryoablation had a similar therapeutic effect compared with MWA in the treatment of pulmonary malignant tumors, but was associated with less pain.