MRI does not reduce biopsies in diagnosing breast cancer

BMJ 2004; 329 doi: (Published 09 December 2004) Cite this as: BMJ 2004;329:1362
  1. Scott Gottlieb
  1. New York

    Magnetic resonance imaging (MRI) may be a more sensitive test for detecting clinically significant breast lesions than mammography, but it does not reduce the need for subsequent tissue sampling once suspicious lesions are identified.

    Mammography is the most common imaging tool used to detect clinically hidden breast cancer, but it has limitations in both sensitivity and specificity. Previous research has shown that 27-37% of patients have lesions visible on MRI that are not seen on a mammogram (Radiology 1993;187: 493-501

    In this study, David Bluemke of the Johns Hopkins University School of Medicine, Baltimore, and colleagues did a study to determine the accuracy of breast MRI in conjunction with mammography for the detection of breast cancer in patients with suspicious mammographic or clinical findings (JAMA 2004;292: 2735-42.

    The international breast MRI consortium study was done at 14 university hospitals in the United States and Europe from June 1998 to October 2001. The study included 821 patients referred for breast biopsy based on suspicious mammographic, clinical, or ultrasound findings. Patients were prospectively evaluated with MRI examinations before breast biopsy.

    All women had high resolution three dimensional MRI of the breast. Patients with suspected breast cancer were asked to return for dynamic MRI no sooner than 18 hours later. All MRI examinations were done at 1.5 T using a dedicated breast coil. A single breast was imaged to maximise the spatial resolution of the MRI. The MRI results were interpreted at each site by investigators blinded to the results of the biopsies.

    The researchers found that MRI correctly detected cancer (ductal carcinoma in situ or invasive cancer) among 356 of 404 women with cancer (sensitivity 88.1%, 95% confidence interval 84.6% to 91.1%; specificity 67.7%, 62.7% to 71.9%).

    The performance of MRI was not significantly affected by mammographic breast density, tumour histology, or menopausal status.

    The authors noted that MRI had a significantly higher positive predictive value (72.4%) than mammography (52.8%). A negative predictive value of 85.4%, however, meant that, in most circumstances, MRI could not rule out breast biopsy for suspicious lesions.

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