Estimating the cost-effectiveness of stereotaxic biopsy for nonpalpable breast abnormalities: a decision analysis model.

Abstract

We examined the clinical and economic trade-offs of shifting from surgical excisional biopsy to stereotaxic core breast biopsy for evaluating non-palpable, mammographically detected breast lesions. A decision analysis model compared strategies beginning with excisional or stereotaxic core biopsy for hypothetical cohorts of 1,000 women. All women with negative initial biopsies had a 6-month follow-up mammogram. Sensitivities and specificities were based on the literature and expert estimates. Pretest probabilities of invasive cancer and in situ cancer were each 10% based on mammographic features. Adjusted costs were based on an audit of patients evaluated at the Medical College of Virginia and physician relative value units. Per 1,000 women, with an expected rate of 100 invasive and 100 in situ cancers, the stereotaxic core biopsy strategy would initially miss 6.7 invasive and 12.4 in situ cases. Most of these would be detected at 6-month follow-ups. Of the women having a stereotaxic core biopsy, 75.7% avoided a surgical procedure. Using stereotaxic core biopsy saved $804 per woman. Continuing to initially use surgical biopsy, total management costs were an additional $42,100 per each case of early detected invasive or in situ cancer. A speculative sensitivity analysis, in which the prognosis of invasive cancer was worse if diagnosis was delayed by 6 months, indicated that surgical biopsy had an incremental cost of $156,700 per additional life year gained. Using conservative estimates for the false-negative rate of stereotaxic core breast biopsy, widespread use of stereotaxic biopsy is projected to have substantial cost savings with a slight compromise in the rate of early detection. Whether the decremental cost-effectiveness is acceptable is dependent on the natural history of cancers whose diagnosis is delayed.