Do 3-D mammograms improve breast cancer screening?
Researchers at the University of Toronto and Sunnybrook Health Sciences Centre have opened a Canadian clinical trial as part of a large-scale, randomized, multi-centre study of 3-D breast mammography for breast cancer screening.
The study, called T-MIST (for Tomosynthesis Mammographic Imaging Screening Trial), will compare 3-D breast mammography, or digital tomosynthesis, to the current standard of digital mammography.
“Our hope is that digital tomosynthesis will take us further, to result in fewer false alarms, potentially a 30 to 40 per cent reduction, to lessen anxiety for patients, and to find up to one-third more of the small, invasive cancers that would be missed with current mammography, and that really need to be treated,” says Roberta Jong, an Associate Professor in the Department of Medical Imaging at U of T and a breast-dedicated Radiologist at Sunnybrook.
Digital tomosynthesis uses the strengths of digital mammography, but instead of taking two X-ray views, tomosynthesis quickly takes up to 15 low-dose images of the breast that are layered into a three-dimensional view. Because information is not superimposed on only two images, tomosynthesis has the potential to create less ambiguous shadows and help avoid missing cancers that may be hidden in surrounding dense breast tissue.
“Smaller studies or studies using only one type of digital tomosynthesis system have shown encouraging results, but to definitively test the technology, we need to conduct research with larger populations, with a randomized method, in varied health care settings — community hospitals and specialized cancer centres — and with multiple tomosynthesis systems,” says Martin Yaffe, a Professor in the Departments of Radiology and Medical Biophysics at U of T who is also a Senior Scientist, Physical Sciences in the Odette Cancer Research Program at Sunnybrook Research Institute.
The researchers are conducting the trial in one of the two sites located in Canada, and are recruiting 2,000 women over 18 months with follow up over a two-year period. The trial is open to women ages 40 years and over who have no past personal history of breast cancer. For more information, potential participants can contact anoma.gunasekara@sunnybrook.ca
The Canadian clinical trials are part of a collaboration with Dr. Etta Pisano, former Dean of Medicine at the Medical University of South Carolina. Prors. Jong and Yaffe were also site co-investigators with Dr. Pisano on the landmark D-MIST (Digital Mammographic Imaging Screening Trial) that reported similar diagnostic accuracy of film and digital mammography but with significantly higher accuracy of digital mammography, among women under age 50 years and women with dense breasts.
The overall randomized trial will be done in about 14 more sites across North America, and will involve 60,000 women.
Watch a video on T-MIST with Prof. Yaffe here.
