New trial explores 3D mammography technology

A landmark Australian trial has taken the first step in determining how new digital 3D mammography technology (also called tomosynthesis) may improve the early detection of breast cancer.

Currently, 2D mammography remains the only proven technology for screening healthy women aged 50-74 years for breast cancer in Australia, and is the standard for Government-funded free BreastScreen services across the country.

However, the BreastScreen Victoria Tomosynthesis in Screening Trial, a collaboration between BreastScreen Victoria, Eastern Health and the University of Sydney with funding from the National Breast Cancer Foundation, has investigated the effectiveness of tomosynthesis - a modified digital mammography unit that creates three-dimensional images of the breast.  This type of screening can increase the accuracy of a mammogram by improving the ability to see through layers of overlapping tissue that can mask tumours or benign changes that can mimic a tumour. Recent international trials have shown that adding 3D-mammography to 2D-mammography improves breast cancer detection, however, prior to this trial there was no data from the Australian health setting.

The trial’s lead investigator, University of Sydney Professor Nehmat Houssami, said that it represented the first and most critical step towards providing evidence on the outcomes of tomosynthesis screening in an Australian population screening context.

“For tomosynthesis to be recommended for adoption in Australia, evidence on its cancer detection capability when used in local programs had to be collected before a larger trial or changes to current screening programs can be looked at,’ Professor Houssami said. “This trial, conducted through BreastScreen Victoria with funding from the National Breast Cancer Foundation, allowed us to conduct a large scale comparative estimate of detection for both tomosynthesis and standard mammography screening.”

The BreastScreen Victoria Tomosynthesis in Screening Trial involved approximately 10,000 women of at least 40 years of age attending Maroondah BreastScreen for routine, biennial screening between August 2017 and November 2018. Of this population, 5018 women were screened using tomosynthesis, with 5166 women moving forward with standard 2D mammography.

The study found that tomosynthesis screening provided a cancer detection of  3.2 additional cancers per 1000 women screened, suggesting that the newer, three dimensional technology does indeed detect more cancers. However, it was found that tomosynthesis produced longer screen reading times and higher doses of radiation required to produce the multiple 3D images.

BreastScreen Victoria’s CEO, Vicki Pridmore, said that the organisation’s participation in the findings could now lead to a broader examination of the two types of screening.  

“BreastScreen Victoria is always in search of the best health and service outcomes for our clients.” Ms Pridmore said.  “New technologies, as trialled here, help us build further evidence to deliver the best possible screening program to Victorian women.