Vol. 20 No. 3 P. 8
Study Supports Mammography at 30 for Some Women
A large-scale study of more than 5 million mammograms found that annual mammography screening beginning at age 30 may benefit women with at least one of three specific risk factors: dense breasts, a personal history of breast cancer, or a family history of breast cancer. The study was presented at RSNA 2018.
The American Cancer Society says that women should have the choice to get an annual mammogram beginning at age 40 and recommends that all women at average risk should be screened annually beginning at age 45. Some other leading professional groups recommend annual mammography screening beginning at age 40, and RSNA supports this recommendation. However, for younger women, the directives are less clear.
“Women under 40 have not been the focus of our attention when it comes to breast cancer screening,” said Cindy S. Lee, MD, an assistant professor of radiology at NYU Langone Health in New York. “Everyone is talking about the 40 to 49 range and not the 30 to 39 age range. It’s difficult to study this group because most women in this age range do not get mammograms, but some of these young women have increased risk for breast cancer and may need earlier and/or supplemental screening.”
For the study, Lee and colleagues compared the performance metrics of screening mammography in women between the ages of 30 and 39 with three specific risk factors vs women aged 40 to 49 without these risk factors, using data from the National Mammography Database (NMD), the largest source of screening mammography outcomes in the United States. The NMD contains information from more than 19 million mammograms, including self-reported patient demographics, clinical findings, mammography interpretations, and biopsy results.
The researchers analyzed data from more than 5.7 million screening mammograms performed on more than 2.6 million women over an eight-year period between January 2008 and December 2015 in 150 facilities across 31 states. The research team compared screening performance metrics among subgroups of women based on age, risk factors, and breast density. Three specific risk factors for breast cancer were evaluated in this study: family history of breast cancer (any first-degree relative regardless of age), personal history of breast cancer, and dense breasts.
“Current breast risk prediction models incorporate different risk factors, which are weighed differently and can produce different results for the same patient. This complexity can lead to confusion and uncertainty for both doctors and patients,” Lee said. “Our study defined ‘increased breast cancer risk’ in a simpler and more inclusive way. Any woman with dense breasts, personal history, or family history of breast cancer in any first-degree relative is considered to have increased risk.” She added that breast density is an important risk factor for breast cancer but is excluded from all risk models except one.
Four performance metrics for screening mammography were calculated for each patient age and risk group: cancer detection rate, recall rate, positive predictive value (PPV) for biopsy recommended, and PPV for biopsy performed. Recall rate is the percentage of patients called back for follow-up testing after a screening exam. PPV reflects the percentage of cancers found among exams for which biopsy was recommended or performed.
In the under 40 group, some of the women had increased risk, either because of dense breasts, family history, or a personal history of breast cancer. Overall, women aged 30 to 34 and 35 to 39 had similar cancer detection rates, recall rates, and PPVs. Cancer detection rates were significantly higher in women with at least one of the three evaluated risk factors. Moreover, compared with women aged 40 to 44 at average risk, incidence screening—at least one prior screening examination—of women in their 30s with at least one of the three evaluated risk factors showed similar cancer detection rates and recall rates.
“Women with at least one of these three risk factors may benefit from screening mammography beginning at age 30, instead of 40,” Lee said.
— Source: RSNA
Women Benefit From Mammography Screening Beyond Age 75
Women age 75 years and older should continue to get screening mammograms because of the comparatively high incidence of breast cancer found in this age group, according to a study presented at RSNA 2018. Guidelines on what age to stop breast cancer screening have been a source of confusion in recent years. In 2009, the United States Preventive Services Task Force released controversial guidelines stating there was not enough evidence to assess benefits and harms of screening mammography in women aged 75 and older. However, other professional groups advise that women may continue to undergo mammography screening as long as they are in good health.
“Ongoing debate exists regarding the age to cease screening mammography,” said Stamatia V. Destounis, MD, FACR, FSBI, FAIUM, radiologist at Elizabeth Wende Breast Care, LLC, in Rochester, New York, and a member of Radiology Today’s Editorial Advisory Board. “Our findings provide important data demonstrating that there is value in screening women over 75 because there is a considerable incidence of breast cancer.”
For the study, Destounis and colleagues analyzed data from 763,256 screening mammography exams at Elizabeth Wende Breast Care between 2007 and 2017. Screening-detected cancer was diagnosed in 3,944 patients. Further analysis was performed to identify the number and type of cancers diagnosed among women 75 years of age and older.
There were 76,885 patients (10%) aged 75 and older included in the study. The average age of the patients was 80.4. A total of 645 malignancies were diagnosed in 616 patients, for a cancer rate of 8.4 detections per 1,000 exams in this age group.
“For the relatively small percentage of our screening population that was comprised of women 75 and older, the patients diagnosed in this population made up 16% of all patients diagnosed with screening-detected cancers,” Destounis said.
Researchers also found that 82% of the malignancies diagnosed were invasive cancers, of which 63% were grade 2 or 3, which grow and spread more quickly. Ninety-eight percent of the cancers found were able to be treated surgically. Positive lymph nodes were reported at surgical excision in 7% of the patients. Seventeen cancers were not surgically treated due to advanced patient age or overall degraded patient health.
“Most of the tumors found in this age group were invasive, and almost all of these patients—98%—underwent surgery,” Destounis said.
Mammography plays a critical role in the early detection of breast cancer because it can show changes in the breast up to two years before a woman or her physician can feel them, and early detection leads to better treatment options and improved survival. Destounis advises women older than 75 who are in relatively good health to continue routine screenings.
“The benefits of screening yearly after age 75 continue to outweigh any minimal risk of additional diagnostic testing,” she said.
— Source: RSNA
Digital Mammography Increases Breast Cancer Detection
The shift from film to digital mammography increased the detection of breast cancer by 14% overall in the United Kingdom without increasing the recall rate, according to a major study appearing in the journal Radiology.
“Image quality with digital mammography is improved over that of screen film mammography,” says radiologist and study coauthor Rosalind M. Given-Wilson, MBBS, from St. George’s University Hospitals National Health Service (NHS) Foundation Trust in London. “In particular, digital mammography provides the ability to visualize calcifications and see through denser tissue, and it allows the reader to adjust the image.”
Given-Wilson and colleagues assessed digital mammography’s impact on cancer detection using data from the 80 facilities of the NHS Breast Screening Programme. The huge trove of data combined with estimates of digital mammography usage enabled the researchers to measure the effect of digital mammography in 11.3 million screening exams in women between the ages of 45 and 70.
The overall cancer detection rate was 14% greater with digital mammography, with substantially higher detection of grade 1 and grade 2 invasive cancers—early-stage cancers that could advance to life-threatening disease if not detected and treated early enough. At first screening exams for women aged 45 to 52, digital mammography increased the overall detection rate by 19%. Importantly, the higher sensitivity of digital mammography did not increase the recall rate—the rate at which women are called back for additional screening based on suspicious results.
“This improvement happened in the absence of other changes in the English screening program, such as a change in recall rate or introduction of computer-aided detection, so we can be clear that the increased rate of detection is due to the change in technology,” Given-Wilson says.
Digital mammography increased the detection of some types of cancers more than others. For instance, digital mammography significantly increased the detection of ductal carcinoma in situ (DCIS), an early-stage cancer confined to the milk ducts of the breast, at both first screens and subsequent screens.
“These results confirm that digital mammography is superior to screen film mammography in finding invasive cancers and DCIS,” Given-Wilson says. “Women are more likely to have a cancer detected with a digital mammogram.”
While digital mammography improved detection of grade 1 and 2 cancers, the researchers found no improvement in the detection of grade 3 invasive cancers. Grade 3 cancers are faster growing and more likely to spread than grade 1 and 2 cancers.
The researchers are looking at the radiological features of grade 3 cancers on digital mammography to see whether optimizing the image for these lesions, which are often nonspecific and ill-defined soft tissue densities, can aid detection. They are also studying the relationship between grade 3 cancers and subsequent interval cancers—cancers that appear between screenings.
— Source: RSNA
Novel Technique May Significantly Reduce Breast Biopsies
A novel technique that uses mammography to determine the biological tissue composition of a tumor could help reduce unnecessary breast biopsies, according to a study appearing in the journal Radiology. Mammography has been effective at reducing deaths from breast cancer by detecting cancers in their earliest, most treatable stages. However, many women are called back for additional diagnostic imaging and, in many cases, biopsies, for abnormal findings that are ultimately proven benign. Research estimates this recall rate to be more than 10% in the United States.
“The callback rate with mammography is much higher than ideal,” says the study’s first author, Karen Drukker, PhD, a research associate professor in the department of radiology at the University of Chicago. “There are costs and anxiety associated with recalls, and our goal is to reduce these costs but not miss anything that should be biopsied.”
Drukker and colleagues recently studied a new technique called three-compartment breast (3CB) imaging. John Shepherd, PhD, currently at the University of Hawaii in Honolulu, and his team developed 3CB while he was at the University of California in San Francisco. By measuring the water, lipid, and protein tissue composition throughout the breast, 3CB may provide a biological signature for a tumor. For instance, more water in the tumor tissue might indicate angiogenesis—the production of new blood vessels—an early sign of cancer development.
For the study, the researchers acquired dual-energy mammograms from 109 women with breast masses that were suspicious or highly suggestive of a malignancy—the types of lesions that typically would be biopsied—immediately prior to biopsy, and the ensuing biopsies showed 35 masses to be invasive cancers, while the remaining 74 were benign.
3CB images were derived from the dual-energy mammograms and analyzed along with mammography radiomics, a method that uses AI algorithms to analyze features and patterns in images—some of which are difficult for human perception to detect—developed by Maryellen L. Giger, PhD, and her team at the University of Chicago for use in computer-aided diagnosis on breast images.
The combination of 3CB image analysis and radiomics improved the positive predictive value—the ability to predict cancer—in breast masses deemed suspicious by the breast radiologist. The combined method improved positive predictive value from 32% for visual interpretation alone to almost 50%, with an almost 36% reduction in biopsies. The 3CB-radiomics method missed one of the 35 cancers, for a 97% sensitivity rate.
“These results are very promising,” Drukker says. “Combining 3CB image analysis with mammography radiomics, the reduction in recalls was substantial.”
Drukker says the combined 3CB-radiomics approach has the potential to play an increasingly prominent role in breast cancer diagnosis and perhaps also screening. She noted that 3CB can easily be added to mammography without requiring extensive modifications of existing equipment.
“The patient is already getting the mammography, plus we get all this extra information with only a 10% additional dose of radiation,” she says.
This approach is still experimental, and further work is needed to make it available to patients. The researchers plan to study how the combined approach will help radiologists make their final determinations. They also want to study the approach using digital breast tomosynthesis. A tumor’s unique water-lipid-protein signature may be even clearer with tomosynthesis, Drukker says.
— Source: RSNA