A COST MINIMIZATION APPROACH TO THE DIAGNOSIS OF SKELETAL NEOPLASMS

Objective. Percutaneous needle aspiration (PNA) has been widely used t o diagnose bone malignancies. Successful aspirates hinge on the abilit y of the operator to obtain an adequate or diagnostic sample, and a sk illed cytologist to make a diagnosis on needle aspirates. False-negati ve aspirates could pose a serious problem. This study is designed to e valuate the cost-effectiveness of PNA in the diagnosis of skeletal neo plasms using a cost minimization approach. Design. All PNA performed o ver a 44-month period were reviewed retrospectively. Ninety-four skele tal biopsies were performed to diagnose a clinically or roentgenograph ically suspicious lesion: 69 for a suspected metastatic malignancy, an d 25 for a suspected primary malignancy, The PNA results were collecte d and reviewed, sensitivities and specificities were determined (compa red with open biopsy results or clinical follow-up as the gold standar ds), and the probabilities were applied to a decision tree. Charges we re obtained from the patient's billing and converted into costs by a c ost-charge ratio. Sensitivity analysis was performed to determine the costs of each branch of the decision tree, and ultimately the final co st of the two strategies: (1) PNA for all suspected neoplasms followed by open biopsy for negative and non-diagnostic PNA results, or (2) op en biopsy for all suspected neoplasms. Results. In diagnosing a suspec ted metastatic skeletal neoplasm, PNA had a sensitivity of 88%, a spec ificity of 100%, and a non-diagnostic re suit in 3% of cases. Cost ana lysis determined a savings of $ US 2486 per patient when ''PNA strateg y'' was used instead of ''open biopsy strategy''. In diagnosing a susp ected primary neoplasm, PNA hat a sensitivity 75%, a specificity of 10 0%, and a non-diagnostic result in 16% of cases. Cost analysis determi ned a savings of $ US 954 per patient when ''PNA strategy'' was used i nstead 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 n eoplasms could be reliably diagnosed by PNA, and followed by open biop sy if the PNA result is negative or non-diagnostic, at a significant c ost saving over open biopsy. Diagnosing primary skeletal neoplasms usi ng ''PNA strategy'' offers a slight cost saving compared with ''open b iopsy strategy'', but too few primary skeletal neoplasms were evaluate d to recommend the best diagnostic approach.