title: Local tumour progression after ultrasound-guided microwave ablation of liver malignancies: risk factors analysis of 2529 tumours.
abstract: OBJECTIVE
  To identify the incidence and risk factors that predict local tumour progression (LTP) after ultrasound-guided percutaneous microwave ablation (MWA) of liver malignancies.
  
  
  METHODS
  One thousand two hundred and nine patients with 2,529 malignant nodules (mean size 2.8 ± 1.4 cm, range 0.9-8.0 cm) were treated by MWA between July 2005 and December 2012. The influence of 11 factors on the risk of LTP was assessed. Univariate Kaplan-Meier and Cox proportional hazard models were used for statistical analysis.
  
  
  RESULTS
  The overall LTP was 4.2 % per tumour and 8.6 % per patient with a median follow-up of 20.3 months. LTP per tumour was 4.3 % for primary liver cancer and 4.1 % for metastases (p = 0.32). The survival of LTP and free-LTP patients at 1, 3, and 5 years was 92.4 %, 71.6 %, and 45.1 %, respectively, and 92.9 %, 70.1 %, and 52.4 %, respectively (p = 0.93). By univariate analysis, tumour location, size and ablation time were significant risk factors of LTP. Multivariate analysis identified tumour size (>3.0 cm) to be the only independent predictor of LTP.
  
  
  CONCLUSIONS
  MWA of liver malignancies achieves a relatively low-incidence LTP, although LTP risk significantly increases if tumour size >3.0 cm. The technique seems to be appropriate even for patients with a tumour at a risk location.
  
  
  CONCLUSIONS
  • Microwave ablation of liver malignancies achieves a low incidence local tumour progression. • LTP risk significantly increases if the tumour size is >3.0 cm. • MWA seems to be appropriate even for patients with a tumour at a risk location.
authors.affiliation: Department of Interventional Ultrasound, Chinese PLA General Hospital, 28 Fuxing Road, Beijing, 100853, China, yu-jie301@hotmail.com.
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-Gang
authors.initials: ZG
authors.lastname: Cheng
authors.forename: Zhi-Yu
authors.initials: ZY
authors.lastname: Han
authors.forename: Meng-Juan
authors.initials: MJ
authors.lastname: Mu
authors.forename: Qin-Ying
authors.initials: QY
authors.lastname: Li
authors.forename: Yan-Mei
authors.initials: YM
authors.lastname: Liu
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017115:Catheter Ablation / Q000379:methods*; D005260:Female; D006801:Humans; D008099:Liver / Q000000981:diagnostic imaging / Q000601:surgery; D008113:Liver Neoplasms / Q000000981:diagnostic imaging* / Q000601:surgery*; D008297:Male; D008872:Microwaves; D008875:Middle Aged; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012307:Risk Factors; D016019:Survival Analysis; D016896:Treatment Outcome; D018084:Ultrasonography, Interventional; D055815:Young Adult