BREAST IMAGING IN 3D
Breast tomosynthesis is based on a well-established radiological concept, that of tomography, the same on which a CT (computed tomography) scanner is based. Basically this means that we are able to obtain multiple projections of a structure from different angles. This has the advantage of disentangling possible overlapping structures that are obtained from a static image taken from a single angle (also known as a 2D image).
Tomosynthesis (also known as breast imaging in 3D) applies the same approach to breast imaging. One of the current pitfalls of standard mammography is that it is difficult to tease out overlapping breast tissue, with the risk of missing small tumours. This proves even more difficult in women with dense (very glandular) breasts. Varying degrees of dense breasts are seen in about 60% of women that undergo breast check-ups by mammography. Since 2013 large single centre trials have been published that have shown that breast tomosynthesis, in combination with standard 2D mammography increases cancer detection rates in breast check-ups by some 30%.
One other problem with standard 2D mammography is a high false positive rate (i.e. the reporting radiologist suspects that there is something abnormal, which on further investigation, typically further mammographic views, ultrasound and possibly a biopsy, turns out to be nothing more than overlapping breast tissue). Breast tomosynthesis decreases this false positive rate by approximately 15%.
It is anticipated that over the next few years, when larger trials are finalised, breast tomosynthesis will completely replace 2D imaging. For the time being, standard mammograms still need to be obtained. However if a person opts to undertake a combo scan (combined 2D & 3D breast imaging), as is available at Saint James Hospital Zabbar, the radiation dose is only minimally higher than a standard mammogram and takes only a couple of seconds longer. This will translate into significant health benefits for women who make this choice, with a considerable reduction in anxiety levels, with less need for other tests, possibly avoiding unnecessary biopsies and surgery, at only a slightly higher cost than usual.
Breast tomosynthesis is at present one of the best available technologies for detection of early breast cancer, especially those cancers that are of an aggressive nature.
While all who undergo a mammogram would benefit from tomosynthesis this is especially recommended for:
- younger women between the ages of 40 and 55 years who are more likely to have denser breasts
- women of any age who know from previous mammograms that they have dense breasts
- women who in the past required additional mammographic views or an ultrasound for evaluation of their mammograms (ultrasound may still be required in some cases)
- women who are being followed up for a dubious finding on previous mammograms
- discerning women who want to maximise their chances of detecting breast cancer as early as possible.