Low-dose positron-emission mammography (PEM) may provide high sensitivity for detecting breast cancer and significantly reduce the likelihood of false-positive results, according to a recent study published by Freitas et al in Radiology: Imaging Cancer. The innovative breast imaging technique may lead to more reliable breast cancer screening among a broader range of patients.
Background
Mammography is known to be an effective screening tool for the early detection of breast cancer; however, its sensitivity is reduced by a masking effect in patients with overlying dense fibroglandular tissue. Since almost 50% of the screening population has dense breasts, many of these patients may require additional breast imaging, often with magnetic resonance imaging (MRI), following mammography.
Low-dose PEM is a novel molecular imaging technique capable of providing improved diagnostic performance at a radiation dose comparable to that of mammography. The technology was designed to deliver a radiation dose comparable to that of traditional mammography without the need for breast compression, which can often be uncomfortable for patients.
Study Methods and Results
In the recent study, researchers assigned 25 patients with a median age of 52 years who were recently diagnosed with breast cancer to undergo low-dose PEM with the radiotracer fluorine F-18–labeled fluorodeoxyglucose (FDG). Two breast radiologists then reviewed the low-dose PEM images taken 1 and 4 hours following F-18 FDG injection and correlated the findings with laboratory results.
The researchers found that low-dose PEM displayed comparable performance to MRI, identifying 96% (n = 24/25) invasive tumors. Compared with MRI, the false-positive rate of low-dose PEM was only 16% vs 62%.
In addition to its strong sensitivity and low false-positive rate, the researchers discovered that low-dose PEM could potentially prevent further unnecessary imaging workups and decrease downstream health-care costs compared with MRI.
Conclusions
The researchers highlighted that low-dose PEM may offer potential clinical uses in both screening and diagnostic settings.
"The integration of these features—high sensitivity, lower false-positive rates, cost-efficiency, acceptable radiation levels without compression, and independence from breast density—positions this emerging imaging modality as a potential groundbreaking advancement in the early detection of breast cancer. As such, it holds the promise of transforming breast cancer diagnostics and screening in the near future, complementing or even improving current imaging methods—marking a significant step forward in breast cancer care," emphasized lead study author Vivianne Freitas, MD, MSc, Assistant Professor at the University of Toronto and a staff radiologist in the Breast Imaging Division of the Toronto Joint Department of Medical Imaging at the University Health Network at Sinai Health System and Women's College Hospital.
"For screening, its ability to perform effectively regardless of breast density potentially addresses a significant shortcoming of mammography, particularly in detecting cancers in dense breasts where lesions may be obscured. It also presents a viable option for patients at high risk who are claustrophobic or have contraindications for MRI,” she added.
The researchers suggested the novel technique could also play a critical role in interpreting uncertain mammography results, evaluating the response to chemotherapy, and ascertaining the extent of disease in patients with newly diagnosed breast cancer such as involvement of the other breast. They are currently investigating whether low-dose PEM can help reduce the high false-positive rates typically associated with MRI scans. If low-dose PEM is found to lower these rates, it could significantly lessen the emotional distress and anxiety linked to false-positive results.
Further, the novel technique might lead to a decrease in unnecessary biopsies and treatments. Nonetheless, more studies are needed to determine low-dose PEM's exact role and efficacy in the clinical setting.
"While the full integration of this imaging method into clinical practice is yet to be confirmed, the preliminary findings of this research are promising, particularly in demonstrating the capability of detecting invasive breast cancer with low doses of F-18 FDG. This marks a critical first step in its potential future implementation in clinical practice," Dr. Freitas concluded.
Disclosure: For full disclosures of the study authors, visit pubs.rsna.org.
