Ultrasound, 3-D mammography effectively detect cancers in dense breasts

The addition of tomosynthesis or ultrasound after a negative mammogram effectively detected missed cancers in women with dense breasts, according to interim results from a prospective comparative trial presented at the 10th European Breast Cancer Conference.

Although ultrasound better detected incremental breast cancers than tomosynthesis — a form of 3-D mammography — tomosynthesis still identified more than 50% of the additional breast cancers diagnosed in these women, according to the results, which were simultaneously published in Journal of Clinical Oncology.

“These findings will have immediate implications for both screening practice and for guiding new research in dense breasts,” Nehmat Houssami, MBBS, MPH, PhD, professor of public health at University of Sydney, said in a press release. “In many countries, such as the U.K. and Australia, using additional screening tests for dense breasts is not recommended routinely by screening programs. But in other countries — such as the U.S., where legislation mandates that women should be informed about their breast density and the availability of extra tests — these findings will be very relevant.”

Wendie A. Berg, MD, PhD, FACR

Ultrasound and tomosynthesis can detect breast cancer in mammography-negative dense breasts, according to study background. However, these modalities have not been directly compared in prospective trials.

Houssami and colleagues conducted the Adjunct Screening with Tomosynthesis or Ultrasound in Mammography-Negative Dense Breasts (ASTOUND) trial to compare incremental breast cancer detection in 3,231 mammography-negative participants (median age, 51 years; interquartile range, 44-78).

All women underwent tomosynthesis and physician-performed ultrasound, with independent interpretation of the imaging.

Key study endpoints included cancer detection rate, number of false-positive recalls and incremental cancer detection rate for each modality.

The researchers identified 24 additional breast cancers, 23 of which were invasive. Ultrasound detected 23 breast cancers (incremental detection rate, 7.1 per 1,000 screens; 95% CI, 4.2-10), whereas tomosynthesis detected 13 (incremental detection rate, 4 per 1,000 screens; 95% CI, 1.8-6.2).

Incremental false-positive recall occurred in 107 participants (3.33%; 95% CI, 2.72-3.96). However, tomosynthesis and ultrasound each were associated with similar rates of false-positive recall for any testing (tomosynthesis, n = 53; ultrasound, n = 65) or for biopsy (tomosynthesis, n = 22; ultrasound, n = 24).

Study limitations included the small number of additional cancers observed and the lack of risk-related data.

“If a woman is concerned that her breasts are very dense on a mammogram, or she has been told that her breasts are very dense and would like more testing, I can use the data from ASTOUND to discuss with her the option of having an ultrasound or a tomosynthesis screen,” Houssami said. “I would discuss with her the pros and cons of adding another test to improve sensitivity for detecting cancer, but would also point out this could have additional harms such as false alarms.”

These findings will play an important role in the development of personalized breast cancer screening recommendations, Wendie A. Berg, MD, PhD, FACR, professor of radiology at University of Pittsburgh Medical Center, wrote in an accompanying editorial.

“Guidelines on these issues are planned, but often limit recommendations to those based on evidence from randomized trials with mortality as an endpoint,” Berg wrote. “Our knowledge of the natural history of breast cancer and results from randomized trials of mammography should inform guidelines for supplemental screening. Methods that improve detection of node-negative invasive cancers should benefit women; a reduction in interval cancers has been shown for screening ultrasound; and a reduction in late-stage disease and improved metastasis-free survival has been shown for MRI. … Further validation of these results is critically needed, as is longer-term follow-up to compare incidence screening results for tomosynthesis and ultrasound.” – by Cameron Kelsall

References:

Berg WA. J Clin Oncol. 2016;doi:10.1200/JCO.2015.65.8674.

Tagliafico AS, et al. Abstract 3LBA. Presented at: 10th European Breast Cancer Conference; March 9-11, 2016; Amsterdam.

Tagliafico AS, et al. J Clin Oncol. 2016;doi:10.1200/JCO.2015.63.4147.

Disclosure: Houssami reports no relevant financial disclosures. Please see the full study for a list of all other researchers’ relevant financial disclosures. Berg reports a consultant role with SuperSonic Imagine.