title: Tumour seeding after percutaneous cryoablation for hepatocellular carcinoma.
abstract: OBJECTIVE
  To assess the rate and risk factors for tumour seeding in a large cohort of patients.
  
  
  METHODS
  Over an 8-year period, 1436 hepatocellular carcinoma (HCC) patients with 2423 tumour nodules underwent 3015 image-guided percutaneous cryoablation sessions [1215 guided by ultrasonography and 221 by spiral computed tomography (CT)]. Follow-up CT or magnetic resonance imaging was performed every 3 mo. The detailed clinical data were recorded to analyse the risk factors for seeding.
  
  
  RESULTS
  The median follow-up time was 18 (range 1-90) mo. Seeding was detected in 11 patients (0.76%) at 1-24 (median 6.0) mo after cryoablation. Seeding occurred along the needle tract in 10 patients and at a distant location in 1 patient. Seeded tumours usually showed similar imaging and histopathological features to the primary HCCs. Univariate analyses identified subcapsular tumour location and direct subcapsular needle insertion as risk factors for seeding. Multivariate analysis showed that only direct subcapsular needle insertion was an independent risk factor for seeding (P = 0.017; odds ratio 2.57; 95%CI: 1.47-3.65). Seeding after cryoablation occurred earlier in patients with poorly differentiated HCC than those with well or moderately differentiated HCC [1.33 ± 0.577 mo vs 11.12 ± 6.896 mo; P = 0.042; 95%CI: (-19.115)-(-0.468)].
  
  
  CONCLUSIONS
  The risk of seeding after cryoablation for HCC is small. Direct puncture of subcapsular tumours should be avoided to minimise seeding.
authors.affiliation: Center of Therapeutic Research for Hepatocellular Carcinoma, 302 Hospital of PLA, Beijing 100039, China.
authors.forename: Chun-Ping
authors.initials: CP
authors.lastname: Wang
authors.forename: Hong
authors.initials: H
authors.lastname: Wang
authors.forename: Jian-Hui
authors.initials: JH
authors.lastname: Qu
authors.forename: Yin-Ying
authors.initials: YY
authors.lastname: Lu
authors.forename: Wen-Lin
authors.initials: WL
authors.lastname: Bai
authors.forename: Zheng
authors.initials: Z
authors.lastname: Dong
authors.forename: Xu-Dong
authors.initials: XD
authors.lastname: Gao
authors.forename: Guang-Hua
authors.initials: GH
authors.lastname: Rong
authors.forename: Zhen
authors.initials: Z
authors.lastname: Zeng
authors.forename: Yong-Ping
authors.initials: YP
authors.lastname: Yang
mesh_terms: D000328:Adult; D000368:Aged; D006528:Carcinoma, Hepatocellular / Q000000981:diagnostic imaging / Q000628:therapy*; D015331:Cohort Studies; D003452:Cryosurgery / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008113:Liver Neoplasms / Q000000981:diagnostic imaging / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D012307:Risk Factors; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D014463:Ultrasonography