title: Hepatocellular carcinoma: surveillance CT schedule after hepatectomy based on risk stratification.
abstract: OBJECTIVE
  To evaluate alternative schedules for surveillance computed tomography (CT) for patients who underwent hepatectomy for hepatocellular carcinoma ( HCC hepatocellular carcinoma ) and to demonstrate an appropriate schedule on the basis of stratification for risk of recurrence.
  
  
  METHODS
  CT and pathologic reports for consecutive patients with HCC hepatocellular carcinoma who underwent hepatectomy at one institution were evaluated with institutional review board approval. Univariate and multivariate analyses were performed to identify risk factors for recurrence. Patients were categorized into risk groups on the basis of classification and regression tree analysis. Average recurrence detection rates ( RDR recurrence detection rate s) between consecutive CT scans were calculated for existing and alternative surveillance schedules for each risk group, and the difference in RDR recurrence detection rate was determined by using the Student t test. A P value of less than .05 was considered to indicate a significant difference. Expected delay in diagnosis was also computed for the alternative surveillance schedules for each risk group.
  
  
  RESULTS
  Two hundred sixty patients (216 men; mean age, 56.0 years ± 22.5) underwent 2705 CT studies. Independent risk factors for recurrence were microvascular invasion (P = .001), cirrhosis (P = .007), and tumor multiplicity (P = .001). Three risk groups (low, intermediate, and high) were identified. For low- and intermediate-risk groups, average RDR recurrence detection rate was not significantly different in the first 2 years after hepatectomy when the interval was extended from 3 months (3.3% and 4.6%, respectively) to 4 months (4.3% [expected delay, 16 days] and 6.1% [expected delay, 18 days], respectively) or for the subsequent 3 years when the interval was extended from 6 months (1.3% and 3.5%, respectively) to 12 months (2.5% [expected delay, 72 days] and 7.0% [expected delay, 103 days], respectively). This alternative schedule included five (35.7%) fewer CT scans than the 14 in the original schedule, and a reduction in radiation dose and cost during the 5-year follow-up period.
  
  
  CONCLUSIONS
  Posthepatectomy surveillance CT schedules may be tailored and optimized according to stratification by risk of recurrence to reduce the frequency of CT scans without compromising surveillance benefits.
authors.affiliation: From the Departments of Diagnostic Radiology (D.L., P.L.K.) and Surgery (A.C.Y.C., R.T.P.P.), Queen Mary Hospital, University of Hong Kong, 102 Pokfulam Rd, Hong Kong; and School of Nursing, Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong (D.Y.T.F.).
authors.forename: Dan
authors.initials: D
authors.lastname: Liu
authors.forename: Daniel Y T
authors.initials: DY
authors.lastname: Fong
authors.forename: Albert C Y
authors.initials: AC
authors.lastname: Chan
authors.forename: Ronnie T P
authors.initials: RT
authors.lastname: Poon
authors.forename: Pek-Lan
authors.initials: PL
authors.lastname: Khong
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D006528:Carcinoma, Hepatocellular / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery*; D003287:Contrast Media; D005260:Female; D006498:Hepatectomy; D006801:Humans; D008113:Liver Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011159:Population Surveillance; D011183:Postoperative Complications / Q000000981:diagnostic imaging* / Q000473:pathology; D011829:Radiation Dosage; D012189:Retrospective Studies; D012307:Risk Factors; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media