title: Effectiveness and cost-effectiveness of sentinel lymph node biopsy compared with axillary node dissection in patients with early-stage breast cancer: a decision model analysis.
abstract: BACKGROUND
  Sentinel lymph node biopsy (SLNB) is less invasive than axillary lymph node dissection (ALND) for staging early breast cancer, and has a lower risk of arm lymphoedema and similar rates of locoregional recurrence up to 8 years. This study estimates the longer-term effectiveness and cost-effectiveness of SLNB.
  
  
  METHODS
  A Markov decision model was developed to estimate the incremental quality-adjusted life years (QALYs) and costs of an SLNB-based staging and management strategy compared with ALND over 20 years' follow-up. The probability and quality-of-life weighting (utility) of outcomes were estimated from published data and population statistics. Costs were estimated from the perspective of the Australian health care system. The model was used to identify key factors affecting treatment decisions.
  
  
  RESULTS
  The SLNB was more effective and less costly than the ALND over 20 years, with 8 QALYs gained and $883,000 saved per 1000 patients. The SLNB was less effective when: SLNB false negative (FN) rate >13%; 5-year incidence of axillary recurrence after an SLNB FN>19%; risk of an SLNB-positive result >48%; lymphoedema prevalence after ALND <14%; or lymphoedema utility decrement <0.012.
  
  
  CONCLUSIONS
  The long-term advantage of SLNB over ALND was modest and sensitive to variations in key assumptions, indicating a need for reliable information on lymphoedema incidence and disutility following SLNB. In addition to awaiting longer-term trial data, risk models to better identify patients at high risk of axillary metastasis will be valuable to inform decision-making.
authors.affiliation: NHMRC Clinical Trials Centre, University of Sydney, Locked Bag 77, Camperdown, New South Wales 2050, Australia. hannah.verry@ctc.usyd.edu.au
authors.forename: H
authors.initials: H
authors.lastname: Verry
authors.forename: S J
authors.initials: SJ
authors.lastname: Lord
authors.forename: A
authors.initials: A
authors.lastname: Martin
authors.forename: G
authors.initials: G
authors.lastname: Gill
authors.forename: C K
authors.initials: CK
authors.lastname: Lee
authors.forename: K
authors.initials: K
authors.lastname: Howard
authors.forename: N
authors.initials: N
authors.lastname: Wetzig
authors.forename: J
authors.initials: J
authors.lastname: Simes
mesh_terms: D001365:Axilla; D001943:Breast Neoplasms / Q000175:diagnosis / Q000473:pathology*; D003362:Cost-Benefit Analysis; D003661:Decision Support Techniques; D005260:Female; D006801:Humans; D008197:Lymph Node Excision / Q000191:economics*; D008207:Lymphatic Metastasis; D008390:Markov Chains; D009367:Neoplasm Staging / Q000379:methods*; D016032:Randomized Controlled Trials as Topic; D012680:Sensitivity and Specificity; D021701:Sentinel Lymph Node Biopsy / Q000191:economics*