Tomosynthesis – a new X-ray cancer screening method – detects up to 40% more breast cancer cases than traditional mammography, concludes a new study from Lund University, Sweden.
A total of 7 500 women, aged 40-74, were tested for breast cancer, with 68 receiving a positive diagnosis. Of these, 46 were picked up by both modalities, 21 by tomosynthesis alone and 1 by the two-view digital mammography (or DM) alone, proving the superiority of the new approach.
The one-view digital breast tomosynthesis (or DBT for short) is a three-dimensional X-ray technique that works on the same principle as tomography and makes it easier for health professionals to detect tumours in breast tissue. The images are acquired from different angles, meaning they can show multiple thin layers of the breast, whereas traditional mammograms represent all of the tissue in a single image, thereby complicating early detection of malignancy.
The paper states up to 15-30% “of all cancers may be missed, mainly due to the anatomic noise of the breast, i.e., normal breast tissue overlapping and obscuring the lesion of interest. This applies especially to dense breasts.”
Tomosynthesis was also found to reduce the discomfort of the screening procedure, as it requires much less compression of the breast and emit significantly lower amounts of harmful radiation, making the technique safer.
The study authors pointed out that, owing to these benefits and the ready availability of the equipment on the market, transitioning to the new approach would be relatively straightforward.
“We see a change as inevitable. Breast tomosynthesis will be introduced, it is just a question of when and on what scale,” explained Sophia Zackrisson and Kristina Lång, both radiologists at the Skåne University Hospital in Malmö and researchers at Lund University.
One of the possible challenges to overcome before adopting the new method on a large scale is overdiagnosis. According to estimates, the rate for that in mammography is 10-20%, but no studies have yet evaluated the same rate for tomosynthesis.
Another concern is the study’s discovery of increased recall rates, i.e., a higher incidence of women with benign lesions being recalled for further testing, which leads to unnecessary psychological distress and is therefore a drawback in screening. The recall rate after arbitration was 3.8% for DBT and 2.6% for DM – significant, yet relatively low.
“We see five to ten years from now as a possible timeframe for the large-scale introduction of the technique. There is also an aspiration for more personalised screening, and breast tomosynthesis could therefore be one of several methods used,” concluded Zackrisson.
The new technique is currently more expensive than traditional mammography.