Trailblazers use tomosynthesis to improve diagnosis of breast cancer

TORONTO – An advanced form of mammography at the Joint Department of Medical Imaging is enabling radiologists to spot breast lesions with more accuracy than ever before. That’s giving women a better chance to fight breast cancer at an early stage, when the success rates are much higher. It has also strengthened the Joint Department’s position as one of Canada’s leaders in the field of mammography.

“We’re here to bring innovation to our patients so that we can improve their lives,” said Dr. Lawrence White, Radiologist in Chief of the JDMI, which is made up of the multi-site University Health Network, Mount Sinai Hospital, and Women’s College Hospital.

In particular, the organization has implemented three Selenia Dimensions tomosynthesis imaging suites, from Hologic, which take X-ray pictures of the breast and quickly reconstruct the images in three-dimensions. (Hologic is distributed in Canada by Christie InnoMed Inc.)

3D imaging gives the organization’s 10 breast imaging radiologists a better look at the breast tissue than standard digital X-ray images – just as three-dimensional CT images can provide a better view of certain body structures than traditional, two-dimensional X-rays.

But just to make sure they’ve got all the bases covered, UHN added new “C-View” software in May that enables the tomosynthesis machines to produce two-dimensional scans at the same time as the 3D images are being taken.

That means the radiologists can scour both the 2D and 3D images for tell-tale signs of cancer, without subjecting patients to two sets of exams and the additional X-rays they would require.

“We’re reducing the radiation dose by 50 percent, and at the same time, catching significantly more tumours,” said Dr. Pavel Crystal, Divisional Head, Breast Imaging, at the Joint Department of Medical Imaging.

The combined 2D/3D breast imaging technology is the first implementation of its kind in Canada.

The Hologic Selenia Dimensions imaging suites were originally installed a few years ago. One of the machines was recently upgraded with the C-View solution, a change that involved both software and hardware. The investment was well worth it.

“We’ve had cases where we saw cancer, when we wouldn’t have with standard mammography,” commented Dr. Rachel Fleming, a breast radiologist with the JDMI.

“There have been dozens of these cases,” added Dr. Crystal.

There are proven benefits to tomosynthesis, Dr. Crystal said, referring to studies showing the technology enables radiologists to catch 33 percent more tumours than by using standard film screen or digital X-ray mammography.

That’s tremendously important, as the earlier you can identify a tumour, the better the chances of treating it and keeping the patient alive. So when it comes to tomosynthesis, the JDMI physicians agree the technology is the way of the future.

Indeed, radiologists and hospital managers from across Canada and around the world visit the UHN to find out more about how tomosynthesis is implemented in clinical practice and how to use this technology to increase their cancer detection rate. One such example is an education course on tomosynthesis taught by Dr. Supriya Kulkarni, Radiologist, JDMI, at the University of Toronto’s Advanced Imaging and Education Centre. This is the only course of its kind in Canada.

Dr. Fleming also pointed out that tomosynthesis reduces the call-back rate – the numbers of women who must return for another X-ray exam because something wasn’t clear on the original image. Typically, 5-10 percent of women are called back after undergoing a standard mammogram. “Tomosynthesis reduces this recall rate by 15 percent,” she said.

Paul Cornacchione, Clinical Director, JDMI, noted this not only reduces anxiety in the women, who are frightened when they have to return for another X-ray, but it also improves patient flow at the hospital. “It allows more throughput,” said Cornacchione. “You don’t need to take more views.”

Dr. Fleming observed that tomosynthesis files are quite large, and reading a tomosynthesis exam takes longer than a standard mammogram. “It takes double the time, and maybe a little more,” she said.

Nevertheless, the additional time and effort translates into identifying approximately 33 percent more tumours than ever before, sooner rather than later. “It’s well worth the investment,” said Dr. Fleming.

The JDMI has 10 mammography machines across its sites and aims to install tomosynthesis upgrades on their mammo units at Women’s College and Mount Sinai Hospitals in the near future; currently, the three Hologic tomosynthesis suites are all located at the Princess Margaret Cancer Centre.

The JDMI conducted a total of 58,785 mammography exams in 2013/2014, of which 17,484 were performed at the Princess Margaret hospital.

The department’s 10 breast imaging radiologists are all skilled in interpreting both 2D and 3D images. In addition to these highly specialized physicians, the organization also employs 20 technologists in mammography.

While the JDMI has surged to the forefront of mammography in Canada through the use of tomosynthesis, it has a long history of leadership in this area. “We went digital long ago,” commented Catherine Wang, executive director of the JDMI.

“We had the first DR breast implementation in all of North America, and we were the first organization in Canada to be completely digital for mammography.”

That leadership continues, said Dr. White, as the department has committed itself to pioneering personalized medicine – the application of genetic information, specific to an individual, to the treatment of cancer and other diseases.