Setting The study setting was secondary care. The economic study was carried out in the USA.

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1 Stereotactic breast biopsy of noncalcified lesions: a cost-minimization analysis comparing 14-gauge multipass automated core biopsy to 14- and 11-gauge vacuum-assisted biopsy Soo M S, Kliewer M A, Ghate S, Helsper R S, Rosen E L Record Status This is a critical abstract of an economic evaluation that meets the criteria for inclusion on NHS EED. Each abstract contains a brief summary of the methods, the results and conclusions followed by a detailed critical assessment on the reliability of the study and the conclusions drawn. Health technology The use of disposable 14-gauge large core needles (Bard, Covington) used with a multipass automated gun technique for stereotactic core biopsy of noncalcified breast lesions was examined. This was compared with the use of vacuumassisted 14- and 11-gauge probes (Mammotome; Biopsys Medical, Irvine). Type of intervention Diagnosis. Economic study type Cost-effectiveness analysis. Study population The study population comprised women with noncalcified breast lesions. Setting The study setting was secondary care. The economic study was carried out in the USA. Dates to which data relate The dates to which the effectiveness and resource use data related were not reported. The price year was not reported. Source of effectiveness data The effectiveness data were derived from a single study. Link between effectiveness and cost data The costing was undertaken on the same patient sample as that used in the effectiveness study. However, it was unclear whether the costing analysis was retrospective or prospective. Study sample No sample size was determined in the planning phase of the study. In addition, power calculations were not performed retrospectively. During a 3-year period, 706 imaging-guided core biopsies were performed at the authors' institution. Of these, 470 (67%) were performed under stereotactic guidance and 236 (33%) under sonographic guidance. One hundred and ninety-three (41%) of the stereotactic biopsies were performed on noncalcified breast lesions. These biopsies were then grouped according to the type of needle used. A multipass automated gun with 14-gauge needle was used in 76 patients, 14-gauge vacuum-assisted probes were used in 78 patients, and 11-gauge vacuum-assisted probes were used in 39 patients. Page: 1 / 5

2 Study design This was a prospective cohort study that was undertaken at a single institution. Allocation to one of the three needles was related to biopsy date, based on needle availability in the market and not related to specific imaging characteristics of the lesions. If the biopsy sample was considered adequate and a concordant histologic diagnosis was noted, then a 12-month follow-up was recommended. For adequate samples resulting in a less specific but benign result a 6-month follow-up was recommended. The mean follow-up for patients requiring short-term follow-up was 21 months for patients sampled with a 14-gauge automated gun, 17 months for patients sampled with a 14-gauge vacuum-assisted technique, and 38 months for patients sampled with an 11-gauge vacuum-assisted technique. The numbers of patients lost to follow-up were 1, 3 and 11, respectively. If the histologic sample was determined to be discordant, inadequate, or not representative of the entire mammographic lesion, the patient was referred for excisional biopsy of the lesion. Analysis of effectiveness All of the patients included in the study appear to have been accounted for in the analysis. The outcomes used in the decision analytic model were the probability of obtaining an adequate sample using each needle device, and the probability of needing a short-term follow-up mammogram in cases of adequate sampling. Following biopsy procedures, the imaging and histologic concordance of each biopsy were determined by consensus among the four radiologists performing the procedures. The authors did not report the baseline characteristics of the patients. Effectiveness results Adequate concordant samples were found in 95% (72 of 76 biopsies) when using a 14-gauge automated gun, 97% (76 of 78 biopsies) when using the 14-gauge vacuum assisted probe, and 97% (38 of 39 biopsies) when using the 11-gauge vacuum-assisted probe. These differences were not statistically significant. Based on the results from subsequent surgical excision in the case of inadequate sampling, none of the 11- or 14-gauge vacuum-assisted probe biopsies yielded a malignancy; in only one case using the 14-gauge automated gun was a malignancy demonstrated at surgery. Short-term follow up was required in 33% (25 of 76) of lesions sampled with the 14-gauge automated gun, 22% (17 of 78) of lesions sampled with the 14-gauge vacuum-assisted technique, and 15% (6 of 39) of lesions sampled with the 11-gauge vacuum-assisted technique. Of those lesions recommended for short-term follow-up, none were subsequently diagnosed as carcinoma. Clinical conclusions The study found no statistically significant differences in the numbers of concordant adequate samples between the three diagnostic interventions. Modelling A decision tree was used to compare the costs and effects of each of the three diagnostic interventions. Measure of benefits used in the economic analysis The analysis of benefits was based upon the equal effectiveness of the three interventions. Therefore, the economic analysis only included costs and was categorised as a cost-minimisation analysis. Direct costs The direct costs included in the analysis were those of the hospital. These comprised the costs of the three diagnostic procedures, the costs of unilateral follow-up mammogram and the costs of surgical excisional biopsy. Opportunity costs, which would account for the estimated revenue that a biopsy room could generate if devoted to diagnostic studies Page: 2 / 5

3 instead of a biopsy procedure, were not included,. This was because all procedures were performed in a room containing a dedicated prone stereotactic table and diagnostic studies could not be performed in that biopsy room. The costs were calculated using a procedure-based cost accounting system which, according to the authors, provided accurate cost estimates based on detailed accounting at a procedural level. However, as the authors' institution considered these costs proprietary information, ratios representing the relative dollar values of the estimated costs were used instead. The quantities and the costs were not analysed separately. Discounting was not relevant, as the costs were incurred during less than two years, and was therefore not performed. The price year was not reported. Statistical analysis of costs The cost ratios were treated as point estimates (i.e. the data were deterministic). Indirect Costs The indirect costs were not included. Currency US dollars ($). Sensitivity analysis A sensitivity analysis was performed to account for potential variations between different populations. Probabilities (range: 0-100%) and a wide range of costs (range: no cost to 20 times the authors' best estimate) were investigated. One- and two-way sensitivity analyses were performed for all combinations of variables. From this analysis, threshold values were calculated to determine the level at which the costs of performing the biopsy using each type of needle were equivalent. Estimated benefits used in the economic analysis See the 'Effectiveness Results' section. Cost results The 14-gauge vacuum-assisted strategy was 1.19 times more expensive than the multipass automated gun strategy, while the 11-gauge vacuum-assisted strategy was 1.22 times more expensive than this strategy. The costs of complications were not included in the costing since no significant complications occurred during the procedures. Synthesis of costs and benefits The costs and benefits were not combined. The sensitivity analysis on the cost of the automated gun showed that, at a fixed probability of adequate sample, the 14-gauge automated gun technique would be the preferred strategy if the cost of the device increased up to 2.78 times its current cost. In addition, it would remain the preferred strategy until the costs of the 14- and 11-gauge vacuumassisted probes decreased to below 70% and 78%, respectively, of their current cost. The analysis also showed that when the cost of needles was fixed and the probability of an adequate sampled varied, the 14-gauge automated gun technique strategy was preferred as long as its success rate was greater than 93.8% and 93.6% when compared with the 14- and 11-gauge vacuum-assisted techniques, respectively. Page: 3 / 5

4 Authors' conclusions From a cost standpoint, the 14-gauge automated gun technique was the preferred strategy. CRD COMMENTARY - Selection of comparators A justification was given for choosing 14- and 11-gauge vacuum-assisted biopsy techniques as the comparators. They represented commonly used and readily available biopsy devices. You should decide if these comparators represent current practice in your own setting. Validity of estimate of measure of effectiveness The analysis was based on a prospective cohort study, which was appropriate for the study question. The study sample should have been representative of the study population as there was no sample selection. However, since the authors did not report any baseline characteristics of the patients, it is not possible to determine whether any differences in baseline characteristics could have confounded the authors' results. This factor will also limit the external validity of the study. Appropriate statistical analyses were performed to test for statistically significant differences between the three groups. However, as no power calculations were reported, the sample size might have been too small and the study might have had insufficient power to detect meaningful differences in outcomes between the three groups. Validity of estimate of measure of benefit The analysis of benefits was based upon the equal effectiveness of the three interventions. Thus, the economic analysis only included costs and was categorised as a cost-minimisation analysis. Validity of estimate of costs All the categories of cost relevant to the perspective adopted were included in the analysis. In addition, no major cost components appear to have been omitted from the analysis. As the times required to perform the biopsy procedures were shown to be not significantly different for the three devices, the authors noted that the exclusion of opportunity costs was unlikely to have affected the results. The costs and the quantities were not reported separately, which will limit the generalisability of the results. The costs were derived from the authors' institution using a micro-costing approach. However, only cost ratios were reported in the study, as it could be used by insurance companies and health maintenance organisations to reduce reimbursements for radiologic procedures. Appropriate sensitivity analyses of the costs were performed, using ranges that appear to have been appropriate. The costs were incurred during less than two years, and hence were not discounted. The price year was not reported, which may hinder the generalisability of the results. Other issues The authors reported that there were no studies considering clinical outcomes and costs in the selection of the three biopsy procedures for noncalcified lesions. The issue of generalisability to other settings was partially addressed in the sensitivity analysis. The authors do not appear to have presented their results selectively and their conclusions reflected the scope of the analysis. The authors reported a further limitation to their study. They did not factor into the cost analysis the availability of suction in the vacuum-assisted techniques to decompress a potential haematoma in the biopsy cavity. The authors also reported that it would have been preferable to have reported actual costs, rather than cost ratios, to make their results more generalisable. Implications of the study Although the study supported the use of the 14-gauge automated gun, the authors reported that some radiologists might still prefer to use the vacuum-assisted device, based on a perception of faster acquisition of tissue and other personal issues that could influence their decisions. The authors suggest that future cost analyses could help drive the market to lower costs of the more expensive vacuum-assisted probes. Page: 4 / 5

5 Powered by TCPDF ( Source of funding None stated. Bibliographic details Soo M S, Kliewer M A, Ghate S, Helsper R S, Rosen E L. Stereotactic breast biopsy of noncalcified lesions: a costminimization analysis comparing 14-gauge multipass automated core biopsy to 14- and 11-gauge vacuum-assisted biopsy. Clinical Imaging 2005; 29(1): PubMedID Other publications of related interest Soo MS, Ghate S, DeLong D. Stereotactic biopsy of non-calcified breast lesions: utility of a vacuum assisted technique compared to multipass automated gun technique. Clinical Imaging 1999;23: Philpotts LE, Hooley RJ, Lee CH. Comparison of automated versus vacuum-assisted biopsy methods for sonography guided core biopsy of the breast. AJR. American Journal of Roentgenology 2003;180: Liberman L, Sama MP. Cost-effectiveness of stereotactic 11-gauge directional vacuum-assisted breast biopsy. AJR. American Journal of Roentgenology 2000;175:53-8. Indexing Status Subject indexing assigned by NLM MeSH Biopsy /economics /instrumentation /methods; Biopsy, Needle /economics /instrumentation; Breast /pathology; Breast Neoplasms /pathology; Costs and Cost Analysis; Decision Support Techniques; Female; Humans; Vacuum AccessionNumber Date bibliographic record published 31/01/2006 Date abstract record published 31/01/2006 Page: 5 / 5