title: Needle track seeding after percutaneous radiofrequency ablation of hepatocellular carcinoma: 14-year experience at a single centre.
abstract: OBJECTIVE
  To determine the incidence, risk factors and prognosis associated with needle track seeding after percutaneous radiofrequency ablations (RFA) for hepatocellular carcinoma (HCC) with a long-term follow-up.
  
  
  METHODS
  A total of 741 HCC patients undergoing percutaneous RFA were retrospectively analysed. Mean follow-up interval was 34.3 ± 26.8 months. All seeding neoplasms were diagnosed by imaging modalities with or without pathological evaluation. Risk factors, including Child-Pugh grading, tumour size, number, location, serum alpha-fetoprotein (AFP) level, track number, biopsy before RFA and electrode type were performed by univariate analysis. Further therapy and survival of seeding after RFA were assessed. Survival analysis was analysed by Kaplan-Meier method.
  
  
  RESULTS
  Twelve patients (12 tumours) were diagnosed as seeding. It corresponds to an incidence of 1.6% (12/741) per patient and 0.9% (12/1341) per tumour. Seeding developed an average of 14.0 ± 8.1 months (6-33 months). Significant risk factors included tumour >3 cm (p = 0.031), subcapsular tumour (p = 0.031), biopsy before RFA (p = 0.001) and non-cool-tip electrode (p = 0.034). Eight patients received local therapy and four cases only received systematic therapy for uncontrolled advanced hepatic tumour or distal metastasis. Of eight patients receiving local therapy, one patient had local recurrence 16 months later and other seven patients did not have local recurrence for 3-73 months. The cumulative survival rates after seeding were 55.6%, 27.8%, 9.3% at 1, 3 and 5 years, respectively.
  
  
  CONCLUSIONS
  Needle track seeding is a rare delayed complication after percutaneous RFA. Tumour >3 cm, subcapsular tumour, biopsy before RFA and non-cool-tip electrode are potential risk factors for seeding. Local therapies are effective methods for seeding patients.
authors.affiliation: a Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Department of ultrasound , Peking University Cancer Hospital and Institute , Beijing , China.
authors.forename: Zhang
authors.initials: Z
authors.lastname: Zhong-Yi
authors.affiliation: a Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Department of ultrasound , Peking University Cancer Hospital and Institute , Beijing , China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Wei
authors.affiliation: a Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Department of ultrasound , Peking University Cancer Hospital and Institute , Beijing , China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Kun
authors.affiliation: a Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Department of ultrasound , Peking University Cancer Hospital and Institute , Beijing , China.
authors.forename: Dai
authors.initials: D
authors.lastname: Ying
authors.affiliation: a Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Department of ultrasound , Peking University Cancer Hospital and Institute , Beijing , China.
authors.forename: Wu
authors.initials: W
authors.lastname: Wei
authors.affiliation: a Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Department of ultrasound , Peking University Cancer Hospital and Institute , Beijing , China.
authors.forename: Lee
authors.initials: L
authors.lastname: Jung-Chieh
authors.affiliation: a Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Department of ultrasound , Peking University Cancer Hospital and Institute , Beijing , China.
authors.forename: Chen
authors.initials: C
authors.lastname: Min-Hua
keywords: Liver malignancy; complication; radiofrequency ablation; seeding