News | Breast Density | July 02, 2018

Norwegian Study Confirms Higher Cancer Rate in Women with Dense Breast Tissue

Study supports value of automated breast density measurement as future standard for breast cancer screening

Norwegian Study Confirms Higher Cancer Rate in Women with Dense Breast Tissue

July 2, 2018 — A large Norwegian study using automated breast density measurements found that women with mammographically dense breast tissue have higher recall and biopsy rates, and increased odds of screen-detected and interval breast cancer. The study, published online in the journal Radiology, supports automated measurements as a future standard to ensure objective breast density classification for breast cancer screening, the researchers said.

Previous studies have shown that women with mammographically dense breasts face a higher risk of breast cancer and missed cancers than those with non-dense breasts, partly because the superimposition of dense breast tissue on mammograms leads to a masking effect, causing some cancers to go undetected. However, the majority of those studies relied on subjective density assessments — most commonly, the radiologist’s subjective interpretation using the American College of Radiology’s Breast Imaging Reporting and Data System (BI-RADS). This approach introduces potential mammogram reader variability into density categorization, said the study’s principal investigator, Solveig Hofvind, Ph.D., from the Cancer Registry of Norway in Oslo.

For the new study, Hofvind and colleagues used automated software to help classify mammographic density in 107,949 women ages 50 to 69 from BreastScreen Norway, a national program that offers women screening every two years. The researchers looked at a total of 307,015 digital screening examinations that took place from 2007 to 2015.

The automated software classified breasts as dense in 28 percent of the screening examinations. Rates of screen-detected cancer were 6.7 per 1,000 examinations for women with dense breast tissue and 5.5 for women with non-dense breasts. Interval breast cancer, or breast cancer detected between screenings — usually by palpation — was 2.8 per 1,000 in the dense breast tissue group and 1.2 for women with non-dense tissue.

The recall rate, or rate at which women are called back for additional examination based on suspicious mammographic findings, was 3.6 percent for women with dense breasts, compared with 2.7 percent in women with non-dense breasts. The biopsy rate of 1.4 percent in the dense breasts group was higher than the 1.1 percent rate for women in the non-dense category.

“The odds of screen-detected and interval breast cancer were substantially higher for women with mammographically dense versus fatty breasts in BreastScreen Norway,” Hofvind said. “We also found substantially higher rates of recalls and biopsies among women with mammographically dense breast tissue.”

Mammographic sensitivity for detecting breast cancer was only 71 percent for women with dense breasts, compared to 82 percent for women with non-dense breasts. Cancers detected at screening were more advanced among women in the dense breast tissue group. Average tumor diameter for screen-detected cancers was 16.6 millimeters (mm) in the dense breasts group, compared to 15.1 mm for the non-dense group. Lymph-node-positive disease was found in 24 percent of women with dense breasts, compared with 18 percent for women with non-dense breasts.

The results add another piece to the puzzle of screening protocols for women with dense breasts. Hofvind noted that more than half of states in the U.S. have enacted breast density legislation, with some states requiring that women be informed about their breast density or that additional breast imaging could be beneficial. However, supplemental screening for women with dense breasts currently is not recommended by any of the major healthcare societies or organizations, and more research is needed before widespread changes are made.

“We need well-planned and high-quality studies that can give evidence about the cost-effectiveness of more frequent screening, other screening tools such as tomosynthesis and/or the use of additional screening tools like MRI [magnetic resonance imaging] and ultrasound for women with dense breasts,” she said. “Further, we need studies on automated measurement tools for mammographic density to ensure their validity.”

In the meantime, Hofvind said, the findings will help inform how automated volumetric density categorization will change population-based screening performance and outcomes through a more objective breast density measurement method.

In an accompanying editorial, “Machine Detection of High Breast Density: Worse Outcomes for Our Patients,” Liane E. Philpotts, M.D., FACR, from Yale School of Medicine wrote, “This study is important for two main reasons: (1) the validation that automated means of density classification can correctly identify a percentage of women with dense tissue, and (2) women with dense tissue have poorer performance of screening mammography. It lends support to the density notification movement along with redoubling efforts towards optimizing supplemental screening methods.”

She added that automated volumetric determination could better standardize density measurements and provide greater confidence that women with dense breast tissue could consistently be identified.

“Breast density is here to stay, and it is in everyone’s best interest to embrace understanding and optimization of breast imaging practice to best address the needs of women with dense tissue,” she concluded.

For more information: www.pubs.rsna.org/journal/radiology

Reference

Hofvind S., Moshina N., Sebuødegård S., et al. "Automated Volumetric Analysis of Mammographic Density in a Screening Setting: Worse Outcomes for Women with Dense Breasts," Radiology. June 26, 2018. https://doi.org/10.1148/radiol.2018172972

Related Content

Damage from concussion alters the way information is transmitted between the two halves of the brain, according to a new study presented today at the annual meeting of the Radiological Society of North America (RSNA).

Image courtesy of RSNA

News | Clinical Trials | December 10, 2019
December 10, 2019 — Damage from...
After receiving acupuncture treatment three days a week during the course of radiation treatment, head and neck cancer patients experienced less dry mouth, according to study results from researchers at The University of Texas MD Anderson Cancer Center

Image by Rudolf Langer from Pixabay 

News | Clinical Trials | December 06, 2019
December 6, 2019 — After receiving acupuncture treatment three days a week during the course of...
Timothy Whelan is a professor of oncology at McMaster University and a radiation oncologist at the Juravinski Cancer Centre of Hamilton Health Sciences. He holds a Canada Research Chair in Breast Cancer Research. Photo courtesy McMaster University

Timothy Whelan is a professor of oncology at McMaster University and a radiation oncologist at the Juravinski Cancer Centre of Hamilton Health Sciences. He holds a Canada Research Chair in Breast Cancer Research. Photo courtesy McMaster University. Photo courtesy of McMaster University

News | Breast Imaging | December 06, 2019
December 6, 2019 — A shorter course of higher-dose radiation treatment to part of the breast is showing promise in wo
MRI Exablate neuro helmet from INSIGHTEC

MRI Exablate neuro helmet from INSIGHTEC. Image courtesy of Ali Rezai, M.D., and RSNA.

News | Clinical Trials | December 03, 2019
December 3, 2019 — Focused ultrasound is a safe and effective way to target and open areas of the blood-brain barrier
Image by Kira Hoffmann from Pixabay  #RSNA19

Image by Kira Hoffmann from Pixabay 

News | Clinical Trials | November 30, 2019
November 30, 2019 — Researchers are trying to identify injury patterns and predict future outcomes for victims of gun
#RSNA19 GE Healthcare introduced Serena Bright, the healthcare industry’s first contrast-enhanced mammography solution for biopsy
News | Mammography | November 30, 2019
November 30, 2019 — To help empower clinicians and patients in their fight against...
This bar graph shows breast cancer presentation by screening interval #RSNA19

This bar graph shows breast cancer presentation by screening interval. Image courtesy of study author and RSNA

News | Breast Imaging | November 28, 2019
November 28, 2019 — Cancers found in patients undergoing annual...
Prof. Dr. Samer Ezziddin from Saarland University/Saarland University Hospital.

Prof. Dr. Samer Ezziddin from Saarland University/Saarland University Hospital. Photo courtesy of Thorsten Mohr/Saarland University

News | Prostate Cancer | November 28, 2019
November 28, 2019 — Reports of new cancer treatments