SY 3b - Multimodality lunch symposium: Dense breast and how to overcome the radiologist's "problem child"
SY 3b - Multimodality lunch symposium: Dense breast and how to overcome the radiologist's "problem child"Wednesday, March 1, 12:15 - 13:45 Room: Studio 2017 Session Type: Satellite Symposium Topics: Evidence-Based Imaging, Breast Moderator: L. J. Pina Insausti (Pamplona/ES) Add session to my schedule In your schedule (remove)
In BI-RADS 2003, the composition was based on the overall density resulting in ACR category 1 ( <25% fibroglandular tissue), category 2 ( 25-50%), category 3 (50-75%) and category 4 (>75%). In BI-RADS 2013, the use of percentages is discouraged, because in individual cases it is more important to take into account the chance that a mass can be obscured by fibroglandular tissue than the percentage of breast density as an indicator for breast cancer risk. Four groups are used: a,b, c and d. The patterns c and d are considered as “dense”. Dense breasts reduce the sensitivity of mammography up to 50%. This is the main limitation of mammography. Fortunately, tomosynthesis can significantly increase the sensitivity of mammography, especially if wide angle is used (increment of detection rate up to +43%). Tomosynthesis is able to reduce the superimposition of tissue and the anatomic noise, allowing the detection of occult lesions. However, at least a small amount of fat surrounding the lesion is needed to be detected. Breast US is widely used as an adjunct to mammography and it improves the sensitivity in dense breasts. But US is a time-consuming, operator-dependent technique that detects too many benign lesions (false-positive results). This is why US cannot be used for population-based screening. MRI is not routinely used for the evaluation of dense breasts, although it can be very useful in some particular cases (preoperative planning, high-risk patients, etc.).
High breast density is associated with an increased risk of breast cancer. However, qualitative measurements of breast density by radiologists may vary and be subjective. Automated VBDA, which is also associated with an increased risk of breast cancer, was developed to provide objective and reproducible measurements. To explore the possibilities and clinical use of VBDA, previous studies have described the agreement between different methods of measuring volumetric density (e.g. by software such as Volpara and Quantra) and radiologists’ assessments in mammography (e.g. qualitative measurements such as BI-RADS and a visual analogue scale) with varying results. DBT is a promising technique and a potential screening modality and the possibility to measure breast density on DBT images is important. Our group has previously compared breast density that was measured by radiologists to measurements obtained from an automated VBDA tool from Siemens using the central projection image in DBT. The results suggested that VBDA could be used in DBT in addition to mammography. Taken together, the use of a robust VBDA is important and seems possible in both mammography and DBT, enabling it to be used in individualised screening programs and in breast cancer risk scores.
MRI is the most sensitive breast cancer imaging technique currently available and recommended for screening women with high breast cancer risk. Women with dense breasts have a moderately increased breast cancer risk. In addition, their dense tissue limits the detection of a tumour with mammography and, therefore, additional screening with MRI could provide a solution for these women as well. However, MRI is not included in screening recommendations for women with dense breasts. The effects of MRI, and also those of other supplemental imaging methods, on breast cancer outcomes remain as yet unclear due to a lack of comparative studies with interval breast cancer rates, stage at diagnosis or breast cancer mortality as the outcome. In this presentation I will outline the present evidence for MRI screening in women with dense breasts, and indicate which type of evidence is still needed to proove its additional value. DENSE, a large randomised controlled trial, that we are currently conducting, has been designed to deliver this proof. It investigates the value of additional MRI compared to usual screening practice, in women with extremely dense breasts and a negative digital mammography. Women are included solely on the basis of their breast density. A fully automatic and validated method is used to estimate mammographic density. The primary outcome is a difference in interval cancer rates between the two arms, the best proxy for a difference in breast cancer mortality.
In most countries breast cancer screening is offered to women between (40)50 and 70(75). The organisation of the screening programs differ from country to country, but in general every two or three years mammography is offered to the participating women. In the past years, several breast imaging techniques have been developed which have the potential to improve breast cancer screening. Digital breast tomosynthesis is one method that has been developed. Multiple low-dose images are obtained and digitally edited and reconstructed as a 3D-image of a breast. The reconstructed 3D-image overcomes the weakness of standard mammography and enables reduction in false-positive findings as results of overlapping tissue. On the other hand, it also enables reduction in the false-negative findings in women with dense breast tissue. Studies have shown that combining ultrasound with mammography in screening settings can significantly improve the rate of found lesions. By adding US to the screening work flow the sensitivity can be improved especially in the dense breast. But US is very time consuming and the specificity goes down (more biopsies are necessary). To overcome these two weaknesses, an “automated breast volume scanner (ABVS)” and elastography can be used. Strain imaging ultrasound technology as Virtual Touch IQ(VTIQ) is a new method being used in breast ultrasound. Various studies have been able to show an increase of the diagnostic specificity without loss of sensitivity when combining the standard ultrasound BIRADS® classification with elastography. The improvement of the specificity will help to eliminate unnecessary breast biopsies in the future.