JCO Early Release, published online ahead of print May 12 2008
Journal of Clinical Oncology, 10.1200/JCO.2007.15.2108
Received November 26, 2007
Accepted March 14, 2008
Accuracy and Surgical Impact of Magnetic Resonance Imaging in Breast Cancer Staging: Systematic Review and Meta-Analysis in Detection of Multifocal and Multicentric Cancer
Nehmat Houssami,* Stefano Ciatto, Petra Macaskill, Sarah J. Lord, Ruth M. Warren, J. Michael Dixon, and Les Irwig
From the Screening and Test Evaluation Program, School of Public Health, National Health and Medical Research Council Clinical Trials Centre, University of Sydney, Sydney, Australia; Department of Diagnostic Imaging, Centro per lo Studio e la Prevenzione Oncologica, Istituto Scientifico della Regione Toscana, Florence, Italy; Department of Radiology, Addenbrooke's Hospital, Cambridge, United Kingdom; and the Edinburgh Breast Unit, Western General Hospital, Edinburgh, Scotland.
* To whom correspondence should be addressed. E-mail: nehmath{at}med.usyd.edu.au
Purpose: We review the evidence on magnetic resonance imaging (MRI) in staging the affected breast to determine its accuracy and impact on treatment.
Methods: Systematic review and meta-analysis of the accuracy of MRI in detection of multifocal (MF) and/or multicentric (MC) cancer not identified on conventional imaging. We estimated summary receiver operating characteristic curves, positive predictive value (PPV), true-positive (TP) to false positive (FP) ratio, and examined their variability according to quality criteria. Pooled estimates of the proportion of women whose surgery was altered were calculated.
Results: Data from 19 studies showed MRI detects additional disease in 16% of women with breast cancer (N = 2,610). MRI incremental accuracy differed according to the reference standard (RS; P = .016) decreasing from 99% to 86% as the quality of the RS increased. Summary PPV was 66% (95% CI, 52% to 77%) and TP:FP ratio was 1.91 (95% CI, 1.09 to 3.34). Conversion from wide local excision (WLE) to mastectomy was 8.1% (95% CI, 5.9 to 11.3), from WLE to more extensive surgery was 11.3% in MF/MC disease (95% CI, 6.8 to 18.3). Due to MRI-detected lesions (in women who did not have additional malignancy on histology) conversion from WLE to mastectomy was 1.1% (95% CI, 0.3 to 3.6) and from WLE to more extensive surgery was 5.5% (95% CI, 3.1 to 9.5).
Conclusion: MRI staging causes more extensive breast surgery in an important proportion of women by identifying additional cancer, however there is a need to reduce FP MRI detection. Randomized trials are needed to determine the clinical value of detecting additional disease which changes surgical treatment in women with apparently localized breast cancer.
