title: A cost minimization approach to the diagnosis of skeletal neoplasms.
abstract: OBJECTIVE
  Percutaneous needle aspiration (PNA) has been widely used to diagnose bone malignancies. Successful aspirates hinge on the ability of the operator to obtain an adequate or diagnostic sample, and a skilled cytologist to make a diagnosis on needle aspirates. False-negative aspirates could pose a serious problem. This study is designed to evaluate the cost-effectiveness of PNA in the diagnosis of skeletal neoplasms using a cost minimization approach.
  
  
  METHODS
  All PNA performed over a 44-month period were reviewed retrospectively. Ninety-four skeletal biopsies were performed to diagnose a clinically or roentgenographically suspicious lesion: 69 for a suspected metastatic malignancy, and 25 for a suspected primary malignancy. The PNA results were collected and reviewed, sensitivities and specificities were determined (compared with open biopsy results or clinical follow-up as the gold standards), and the probabilities were applied to a decision tree. Charges were obtained from the patient's billing and converted into costs by a cost-charge ratio. Sensitivity analysis was performed to determine the costs of each branch of the decision tree, and ultimately the final cost of the two strategies: (1) PNA for all suspected neoplasms followed by open biopsy for negative and non-diagnostic PNA results, or (2) open biopsy for all suspected neoplasms.
  
  
  RESULTS
  In diagnosing a suspected metastatic skeletal neoplasm, PNA had a sensitivity of 88%, a specificity of 100%, and a non-diagnostic result in 3% of cases. Cost analysis determined a savings of $ US 2486 per patient when "PNA strategy" was used instead of "open biopsy strategy". In diagnosing a suspected primary neoplasm, PNA hat a sensitivity 75%, a specificity of 100%, and a non-diagnostic result in 16% of cases. Cost analysis determined a savings of $ US 954 per patient when "PNA strategy" was used instead of "open biopsy strategy". By using "PNA strategy" instead of "open biopsy strategy" at this institution we would have saved $ US 195384 over the 44-month period.
  
  
  CONCLUSIONS
  Metastatic skeletal neoplasms could be reliably diagnosed by PNA, and followed by open biopsy if the PNA result is negative or non-diagnostic, at a significant cost saving over open biopsy. Diagnosing primary skeletal neoplasms using "PNA strategy" offers a slight cost saving compared with "open biopsy strategy", but too few primary skeletal neoplasms were evaluated to recommend the best diagnostic approach.
authors.affiliation: Mallinckrodt Institute of Radiology, St. Louis, MO 63110, USA.
authors.forename: S A
authors.initials: SA
authors.lastname: Ruhs
authors.forename: G Y
authors.initials: GY
authors.lastname: el-Khoury
authors.forename: E A
authors.initials: EA
authors.lastname: Chrischilles
mesh_terms: D001706:Biopsy / Q000191:economics*; D001707:Biopsy, Needle / Q000191:economics* / Q000379:methods; D001859:Bone Neoplasms / Q000175:diagnosis* / Q000473:pathology / Q000556:secondary; D003362:Cost-Benefit Analysis; D003663:Decision Trees; D005251:Fees, Medical; D017721:Hospital Costs; D006801:Humans; D012680:Sensitivity and Specificity