A study published in the April 4 issue of JAMA reveals that ultrasound screening or magnetic resonance imaging (MRI) in addition to annual mammography increases breast cancer detection rates among women with an increased risk of breast cancer and dense breast tissue.
The researchers write:
“Annual ultrasound screening may detect small, node-negative breast cancers that are not seen on mammography. Magnetic resonance imaging may reveal additional breast cancers missed by both mammography and ultrasound screening.”
The study was conducted by Wendie A. Berg, M.D., Ph.D., who previously worked at the American College of Radiology Imaging Network, Philadelphia, and her team in order to determine whether the addition of MRI and ultrasound increased cancer detection in women at increased risk for developing breast cancer.
They enrolled 2,809 women with increased cancer risk and dense breasts at 21 sites to participate in the study. The participants, whose median age was 55 years at enrollment, agreed to three annual independent screens with ultrasound and mammography in randomized order.
Almost 54% of participants had a personal history of breast cancer. After three rounds of both screenings, 612 of the 703 participants who chose to undergo an MRI had complete data.
2,662 participants underwent 7,473 mammogram and ultrasound screenings, 110 of whom had 111 breast cancer events.
The researchers found that mammography detected 59 cancers (53%), including 32 cancers (29%) by ultrasound only, 33 cancers (30%) by mammography only, and 9 cancers (8%) by MRI only after both ultrasound screens and mammography failed to detect cancer.
10% of cancers (11) were not detected by any imaging screen. In the MRI sub-study, 16 out of 612 women were diagnosed with breast cancer.
Among 4,814 incidence screens, 75 participants were diagnosed with cancer in the second and third years combined. Compared with mammography alone, supplemental ultrasound increased cancer detection with each yearly screen:
- 5.3 cancers per 1,000 women in the first year
- 3.7 cancers per 1,000 women in year two and three
An average of 4.3 cancers per 1,000 women for each of the three rounds of annual screening.
The researchers found that the addition of MRI screening helped increase cancer detection in 14.7 per 1,000 women.
127 mammography screens were required to detect 1 cancer, 68 number of screens for supplemental MRI after negative mammography plus ultrasound screening results, and 234 for supplemental ultrasound.
The researchers conclude:
“Despite its higher sensitivity, the addition of screening MRI rather than ultrasound to mammography in broader populations of women at intermediate risk with dense breasts may not be appropriate, particularly when the current high false-positive rates, cost, and reduce tolerability of MRI are considered.”
Written by Grace Rattue