In a study of over a million women, digital breast tomosynthesis (DBT) revealed better breast cancer screening results than regular digital mammography alone.

The findings of the study were published in a Radiology, journal of the Radiological Society of North America (RSNA). In the United States, breast cancer is the most frequent cancer among women.

While breast cancer mortality has been declining since the late 1980s as a result of advances in early identification and treatment, it remains the top cause of cancer death in women.

The five-year relative survival rate of breast cancer when it is detected early in its localised stage is 99%, according to the American Cancer Society. Regular screening is the most reliable method for the early detection of breast cancer.

Screening with two-dimensional (2D) digital mammography alone is still the standard of care at many sites, but it has its limitations due to its inability to detect some cancers.

There is a growing amount of evidence that DBT, a more advanced technology, has a higher breast cancer detection rate due to its ability to capture multiple X-ray images of the breast from different angles rather than the typical single image obtained with a standard 2D mammogram. DBT is especially beneficial for women with denser breast tissue.

"The purpose of our study was to evaluate screening outcomes among a large cohort of women in the United States who were screened with either 2D digital mammography alone or with DBT," said study co-author Emily F. Conant, M.D., FSBI, professor of radiology and chief in the Division of Breast Imaging at the Hospital at the University of Pennsylvania in Philadelphia.

For this retrospective cohort study, Dr Conant and colleagues compiled data from five large healthcare systems across the United States.

The study group consisted of over 1 million women aged 40 to 79 who were screened with either DBT or 2D digital mammography alone between January 2014 and December 2020.

The screening outcomes such as cancer detection and false positive rates were compared across the two screening groups.

"This study was extremely large with most women having at least 2 screens resulting in over 2 million screening exams across five large and diverse health care systems," Dr Conant said.

Compared to 2D digital mammography alone, DBT was associated with important improvements in screening outcomes.

The cancer detection rate for patients screened with DBT was higher at 5.3 per 1,000 screened, compared to 4.5 per 1,000 screened with 2D digital mammography only. DBT also had a lower rate of false positives and recalls from screening.

"We showed that the most important mammographic screening outcomes, increased cancer detection combined with fewer false positives, were significantly improved when women were screened with digital breast tomosynthesis compared to 2D digital mammography alone," Dr Conant said. "Therefore, women should seek out sites that routinely offer breast cancer screening with DBT."