Positron Emission Mammography Scanners Offer an Alternative Screening Method for Women Who Cannot Tolerate MRI

A multisite study of hundreds of women with newly diagnosed breast cancer revealed that positron emission mammography (PEM) might reduce unnecessary breast biopsies. The study found that PEM was significantly more precise at identifying benign and cancerous lesions, in what scientists call positive predictive value (PPV), therefore reducing the number of unnecessary biopsies.

The new data came from a US National Institutes of Health (NIH; Bethesda, MD, USA)-sponsored multisite study. A common physician complaint regarding the use of breast magnetic resonance imaging (MRI) is its tendency to identify suspicious lesions, requiring biopsies, which ultimately are found to be benign.

This finding is a welcomed outcome for women and physicians looking for ways to reduce the patient trauma associated with biopsies and for payers looking to reduce the costs associated with unnecessary procedures. The findings from 388 woman in the study revealed that PEM not only demonstrated a 6% improvement in specificity at comparably high sensitivity, but that PEM also had 31 fewer unnecessary biopsies and 26% higher PPV than breast MR. These findings are also particularly significant for those women who cannot tolerate an MR exam and require an alternate imaging tool.

"The results of this study mean that not only do physicians have an additional, powerful tool to help treat breast cancer but that PEM is a legitimate and better alternative for the 16% of women who cannot tolerate MR due to claustrophobia, metallic implants, body habitus, or gadolinium reaction,” said Wendie Berg, MD, PhD and lead investigator for the trial. Dr. Berg recently published an article in the January 2010 issue in the journal Radiology assessing the reasons why high-risk women who were recommended for a MR breast-screening test refused to take the exam.

PEM scanners are high-resolution breast positron emission tomography (PET) systems that can show the location as well as the metabolic phase of a lesion. This information is vital in determining whether a lesion is malignant and influences the course of treatment. Other imaging systems, such as mammography and ultrasound, show only the location, not the metabolic phase. PEM scanners, which are about the size of an ultrasound system, are manufactured by Naviscan, Inc. (San Diego, CA, USA) and have been commercially available since 2007.

Related Links:
National Institutes of Health
Naviscan