Authors' objectives

To critically review and assess the literature on the performance of magnetic resonance imaging (MRI) as a diagnostic test for primary breast cancer detection in patients with suspicious breast lesions, and to use this information to examine the cost-effectiveness of pre-operative MRI.

Searching

MEDLINE was searched from 1966 to August 1997 using an appropriate search strategy, which was presented in the review. The bibliographies of the references retrieved were manually searched for additional articles and suggestions from experts in the field were compiled. The search was limited to English language articles only.

Study selection

Assessment of study quality

Studies selected for consideration were assessed according to a 10-point subjective quality score scale. Two investigators independently performed the quality assessment. Any disagreements were resolved by consensus.

Data extraction

The data were abstracted from each selected study by using a prospectively designed worksheet, which was presented in the review. Two investigators independently performed the data extraction and any disagreements were resolved by consensus. The categories of data extracted were: patient characteristics, technical factors, and method/validity with mean quality score. Technical factors included ear of publication, high field strength, gadolinium dose of 0.1 mmol/kg, enhancement criteria used for interpretation, and morphological criteria used for interpretation.

Methods of synthesis

Results of the review

A total of 41 (or possibly 37 - there is some ambiguity in the article) studies were subjected to further review and data extraction. Of these, 16 were included in the meta-analysis. The number of patients included in the review was not stated. The reasons for excluding 25 studies were also not given in the review.

The regression analysis showed a slope (b) of -0.21 (95% confidence interval, CI: -0.71, 0.28) and a p-value of 0.37. This indicated approximate symmetry of the summary ROC curve with an intercept (I) of 4.15 (95% CI: 3.06, 5.23). The pooled diagnostic OR for positive breast MRI was 63.1 (95% CI: 21.3, 186.8). The maximal joint sensitivity and specificity of the summary ROC curve was 0.89 (95% CI: 0.82, 0.93). At a sensitivity of 95%, the specificity was 67%.

The data from the 25 excluded studies were summarised. Where data to calculate sensitivity and specificity were available, these were found not to be statistically significantly different from those from the included studies. The year of publication, median reported prevalence of breast cancer, proportion in which sensitivity and specificity were calculable, and the mean quality score (worse) were statistically significantly different between the two groups of studies.

Cost information

The results from the sROC analysis were applied to a prior cost-effectiveness analysis (see Other Publications of Related Interest no.2). The cost-effectiveness of pre-operative MRI relative to that of excisional biopsy was confirmed, but its cost-effectiveness relative to that of needle core biopsy varied widely.

Authors' conclusions

For MRI to be a cost-effective alternative to excisional biopsy for the diagnosis of suspicious breast lesions, its diagnostic test performance must be equal to, or better than the best results in recently published studies.

CRD commentary

The review addressed an appropriate question, although the inclusion and exclusion criteria were not clearly stated in the review. The inclusion of studies in the meta-analysis appeared to depend upon components of quality and validity, although the exact criteria for exclusion were not clear. The literature search was limited to a single electronic database, although it was supplemented by hand checking of bibliographies and consultations with experts. Some important studies may have been missed, particularly as no non-English articles were considered, there was no attempt to identify unpublished literature, and studies published in abstract form only were specifically excluded. The validity of the studies included in the review was formally evaluated; although the details of the quality scale used were not clear, the report discussed verification bias and blinding. Details of the individual primary studies included in the meta-analysis were reported in the review, whereas details of the remaining studies were reported only as summary data. The meta-analysis performed was generally appropriate and well conducted. An additional formal evaluation of heterogeneity in studies included in the meta-analysis, beyond investigation of sROC symmetry, would have been useful. The authors' conclusions are supported by the data presented in the review.

Implications of the review for practice and research

Practice: If the accuracy of MRI, as achieved in the best clinical studies, can be validated, the use of MRI as a pre-operative test in women referred for excisional biopsy could result in a substantial decrease in the number of such referrals.

Research: A multi-institutional study is warranted to validate the accuracy of MRI in clinical practice.

Funding

U.S. National Institutes of Health, grant numbers RO1-CA58358-04 and RO1-CA70362; U.S. Army, grant number RP950855; American Heart Association Student Research Fellowship.

Bibliographic details

Hrung J M, Sonnad S S, Schwartz J S, Langlotz C P. Accuracy of MR imaging in the work-up of suspicious breast lesions: a diagnostic meta-analysis. Academic Radiology 1999; 6(7): 387-397. [PubMed: 10410164]

Other publications of related interest

1. Littenberg B, Moses L. Estimating diagnostic accuracy from multiple conflicting reports: a new meta-analytic method. Med Decis Making 1993;13:313-21. 2. Hrung JM, Langlotz CP, Orel SG, Fox KR, Schnall MD, Schwartz JS. Cost-effectiveness of magnetic resonance imaging and needle core biopsy in the workup of suspicious breast lesions. Radiology 1997;205:538-9.

Indexing Status

Subject indexing assigned by NLM

MeSH

Adult; Aged; Aged, 80 and over; Breast /pathology; Breast Neoplasms /diagnosis /epidemiology; Cost-Benefit Analysis; Female; Humans; Magnetic Resonance Imaging; Middle Aged; ROC Curve; Sensitivity and Specificity

AccessionNumber

11999004437

Database entry date

30/11/2003

Record Status

This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.