Parenchymal enhancement in breast tissue is not an indicator for increased cancer risk

Magnetic resonance tomography (MRT) is the most sensitive procedure for the detection of breast cancer because, contrary to the conventional image-producing procedures (mammography and ultrasound) provides functional information on the blood circulation of the tissue. Generally, this examination is applied in high-risk patients on an annual basis, who have an increased risk for breast cancer based on family history or a special mutation (e.g. BRCA 1). In the process, women are initially injected with a contrast medium, which renders the so-called "background parenchymal enhancement" visible in the MRT. It was already possible to demonstrate in these women that severe background parenchymal enhancement, which indicates increased blood supply and thus an e.g. hormonally activated breast tissue, is associated with an increased risk of the disease.

In the context of the program for the early detection of breast cancer, a routine mammography and possibly a supplementing ultrasound examination is conducted for all other Austrian female patients: www.frueh-erkennen.at).

In the event of an unclear result, it is possible in Austria to perform an MRT for further clarification. Basic medical research attempts to find biomarkers for tumours in order to proceed preventive against breast cancer in the future and to be able to treat it at an early stage. In this context, Barbara Bennani-Baiti and Pascal Baltzer of the Clinic for Radiology and Nuclear Medicine of MedUni Vienna (Manager of breast imaging: Thomas H. Helbich) together with Matthias Dietzel of the University Clinic Erlangen took up the issue whether breast tissue with increased background parenchymal enhancement is generally an indicator for an increased risk for breast cancer, and not just in the risk group. They conducted a cross-sectional study and analysed the findings of a group of 540 patients who had been transferred to an MRT for the further clarification of abnormal findings.

They were able to demonstrate that ultimately only the age was decisive for the risk of breast cancer in this group of patients, who did not have an increased risk for breast cancer due to familial accumulation or known mutations. The activity of the breast, as is demonstrated in the MRT due to the background parenchymal enhancement, is not important in this case. The study data furthermore showed that very active breast tissue in non-high-risk patients points to a lesser age and thus to a lesser risk for the illness. It is also not necessary for these women to undergo further examinations.

However, with their work, Barbara Bennani-Baiti, Matthias Dietzel and Pascal Baltzer demonstrated the importance of the knowledge of background parenchymal enhancement for high-risk patients for a risk assessment of breast cancer. Their results indicate that the changed breast tissue of high-risk patients is more susceptible to degeneration compared to women without these risk factors. If this susceptible tissue now becomes active -- which is also reflected in an increased cell division rate -- cellular degenerations increase, it most probably leads to cancer. In contrast, this activation is not harmful in healthy patients, whose tissue exhibits intact repair mechanisms. The tissue is able to automatically remedy possible defects before it turns into cancer.

Conclusion: High background parenchymal enhancement of the breast visible with MRT in non-high-risk patients primarily indicates a young age; however, for high risk patients, it indicates a clearly increased cancer risk according to current findings and should be considered in the decision-making process for any preventive measures.