title: [Long-term effects of ultrasound-guided microwave ablation in the treatment of small renal cell carcinoma].
abstract: OBJECTIVE
  To evaluate the long-term efficacy of microwave ablation in the treatment of small renal cell carcinoma (RCC).
  
  
  METHODS
  We retrospectively analyzed 140 cases of small cell renal carcinoma (151 lesions with a mean diameter of 2.8±0.8 cm) treated between April, 2006 and October, 2015 with ultrasound-guided microwave ablation with cooled-shaft needle antenna. One microwave ablation antenna was used for tumors less than 2 cm in diameter and 2 antennas were used for larger tumors. The patients received enhanced ultrasound and CT/MRI examinations at 1, 3, and 6 months after the operation and every 6 months thereafter. The overall survival, disease-free survival, and local tumor progression rate of the patients were evaluated.
  
  
  RESULTS
  The response rate of treatment (complete ablation at one month on enhanced images) was 100% in these patients. The local tumor progression rates at 1, 3, and 5 years were 0.9%, 2.0%, and 7.1%, respectively, and the 1-, 3-, and 5-year distant metastasis rates were 1.6%, 2.5%, and 7.9%, respectively. The overall survival rates of the patients at 1, 3, and 5 years were 98.4%, 94.8%, 89.5%, respectively, with disease-free survival rates of 98.4%, 93.0%, and 83.1%, respectively. No major complications occurred in these cases, and multivariate analysis showed that the tumor number (P=0.015) and tumor growth patterns (P=0.049) were independent risk factors that adversely affected the long-term outcome after surgery.
  
  
  CONCLUSIONS
  Our data show that microwave ablation is a safe and effective modality for treatment of renal cell carcinoma.
authors.affiliation: Department of Interventional Ultrasound, General Hospital of PLA, Beijing 100853, China.E-mail: mmj6690@163.com.
authors.forename: Meng-Juan
authors.initials: MJ
authors.lastname: Mu
authors.forename: Jie
authors.initials: J
authors.lastname: Yu
authors.forename: Ping
authors.initials: P
authors.lastname: Liang
authors.forename: Xiao-Ling
authors.initials: XL
authors.lastname: Yu
authors.forename: Zhi-Yu
authors.initials: ZY
authors.lastname: Han
authors.forename: Zhi-Gang
authors.initials: ZG
authors.lastname: Cheng
authors.forename: Fang-Yi
authors.initials: FY
authors.lastname: Liu
authors.forename: Hong-Yan
authors.initials: HY
authors.lastname: Zhai
authors.forename: Xin
authors.initials: X
authors.lastname: Li
mesh_terms: D002292:Carcinoma, Renal Cell / Q000601:surgery*; D018288:Carcinoma, Small Cell / Q000601:surgery*; D017115:Catheter Ablation; D018572:Disease-Free Survival; D006801:Humans; D007680:Kidney Neoplasms / Q000601:surgery*; D008872:Microwaves; D015999:Multivariate Analysis; D012189:Retrospective Studies; D015996:Survival Rate; D016896:Treatment Outcome