Results Summary
What was the research about?
Doctors use imaging tests, alone or together, to detect breast cancer, including:
- Digital mammogram, or DM, a 2D x-ray
- Tomosynthesis, or DBT, a 3D x-ray
- Magnetic resonance imaging, or MRI, which uses magnetic fields and radio waves to take pictures
These tests may differ in their benefits, like detecting cancer early; their harms, like false alarms; and their failures, like missing a cancer diagnosis.
In this project, the research team did two studies to compare imaging tests:
- Study 1 compared DM versus DBT for breast cancer screening. It also compared DM or DBT alone versus DM or DBT plus MRI.
- Study 2 compared having or not having an MRI before surgery for women with breast cancer.
For both studies, the research team looked at women with dense and non-dense breasts separately. Having dense breasts is common but makes it hard to see cancer on DM and DBT and increases breast cancer risk.
What were the results?
Women with dense breasts.
Study 1. DBT and DM didn’t differ in study outcomes, except women who had DM had lower worry about cancer.
Compared with DM or DBT alone, women who also had an MRI had:
- Higher benefits
- Higher harms
- No difference in failures
- More confidence in screening
- More worry about cancer
Study 2. Compared to women with breast cancer who didn’t have an MRI before surgery, women who had one had:
- Higher rates of additional breast cancer detected at six months but not at three years
- More worry about cancer
- No difference in decision quality, conflict, or regret
Women with non-dense breasts.
Study 1. Compared with DM, screening with DBT had:
- Higher benefits
- Lower harms
- No difference in failures or in women’s confidence in screening or worry about cancer
Compared with DM or DBT alone, women who also had an MRI had:
- Higher benefits
- Higher harms
- No difference in failures
- More confidence in screening
- More worry about cancer
Study 2. Compared to women with breast cancer who didn’t have an MRI before surgery, those who had one had:
- Higher rates of additional breast cancer detected at six months but not at three years
- Improved decision quality
- No difference in decision conflict and regret or worry about cancer
What did the research team do?
The research team used data from seven breast imaging registries across the United States. Study 1 included data from 504,150 women who had 1,377,902 screening tests. Study 2 included data from 20,383 women with breast cancer.
Subsets of 2,329 women from study 1 and 957 women from study 2 completed surveys on screening confidence, cancer worry, and decision quality.
Women who had breast cancer, doctors, and advocates gave input during the studies.
What were the limits of the study?
The research team didn’t assign women by chance to the imaging tests. Differences among women, such as reasons for screening, could have affected study outcomes.
Future research could look at other outcomes of imaging tests among women with dense and non-dense breasts.
How can people use the results?
Doctors and women can use the results when considering imaging tests for breast cancer.
Professional Abstract
Objective
To compare, by breast density, the effect of (1) digital mammography versus digital breast tomosynthesis (DBT) with or without breast MRI on breast cancer screening benefits and harms and patient-reported outcomes; (2) having versus not having a preoperative MRI on breast cancer recurrence and patient-reported outcomes among women with breast cancer receiving diagnostic mammography
Study Design
| Design Element | Description |
|---|---|
| Design | Observational: cohort studies |
| Population |
Data from 7 breast imaging registries across the United States: Study 2: 20,383 women ages 18–89 with a pathologically confirmed diagnosis of ductal carcinoma in situ or invasive breast cancer between 2005 and 2020 |
| Interventions/ Comparators |
Study 1:
|
| Outcomes |
Study 1: screening benefits including rate of early-stage cancer detection; screening failures including rates of interval cancer and advanced cancer; screening harms including rates of false-positive recall and biopsy recommendations; patient-reported outcomes including screening confidence and cancer worry Study 2: rate of additional breast cancer detected within 6 months of initial diagnosis; rate of second breast cancer within 3 years; patient-reported outcomes including decision quality, decisional conflict, decision regret, and cancer worry |
| Timeframe | Study 1: Up to 1 year follow-up for study outcomes Study 2: Up to 3-year follow-up for study outcomes starting 1 year after surgery |
These observational cohort studies compared the effect of breast imaging tests on screening benefits, harms, and failures; breast cancer recurrence; and patient-reported outcomes.
Study 1 included breast cancer screening data from 504,150 women who had digital mammography or DBT with or without a screening breast MRI. Study 2 included data from 20,383 women diagnosed with breast cancer who did or did not have a preoperative MRI.
In both studies, researchers analyzed outcomes separately for women with dense and non-dense breasts.
Women who had breast cancer, doctors, and patient advocates provided input during the studies.
Results
Women with dense breasts.
Study 1. Compared with DBT, women who had digital mammography did not differ significantly on clinical and most patient-reported outcomes except having lower cancer worry.
Compared with not having a screening MRI, women who had a screening MRI had higher screening benefits, screening harms, screening confidence, and cancer worry. Screening failures did not differ significantly between women who did and did not have a screening MRI.
Study 2. Compared to women with breast cancer who did not have a preoperative MRI, those who had one had higher rates of additional cancer detected at six months and higher cancer worry. Rates of second breast cancer at three years and other patient-reported outcomes did not differ significantly between women with and without a preoperative MRI.
Women with non-dense breasts.
Study 1. Compared with digital mammography, DBT had higher screening benefits and lower screening harms; screening failures and patient-reported outcomes did not differ significantly.
Compared with not having a screening MRI, women who had a screening MRI had higher screening benefits, screening harms, screening confidence, and cancer worry; screening failures did not differ significantly.
Study 2. Compared to women with breast cancer who did not have a preoperative MRI, those who had one had higher rates of additional cancer detected at six months and higher decision quality; rates of second breast cancer at three years and other patient-reported outcomes did not differ significantly.
Limitations
Researchers did not randomize participants; women may have differed systematically by cancer risk, reasons for screening, or unmeasured confounding variables, such as insurance type.
Conclusions and Relevance
Women with non-dense breasts had improved screening benefits and decreased harms with DBT versus digital mammography. Compared with mammography alone, supplemental MRI was associated with increased screening benefits and harms for women regardless of breast density.
Preoperative MRI was not associated with increased long-term detection of additional breast cancers.
Future Research Needs
Future research comparing screening and diagnostic tests among women with varying breast densities could adjust for additional confounding variables.
COVID-19-Related Study
How the COVID-19 Pandemic Affected Breast Cancer Imaging Services and the Development of Risk-Based Scheduling Approaches
Results Summary
In response to the COVID-19 public health crisis in 2020, PCORI launched an initiative to enhance existing research projects so that they could offer findings related to COVID-19. The initiative funded this study and others.
What was this COVID-19 study about?
During the COVID-19 pandemic, breast cancer imaging clinics had to close briefly or cancel or delay services. Some patients also canceled or delayed exams like mammograms, which are x-rays of the breast. When clinics reopened, they had a backlog of delayed exams. Many also had fewer staff and saw fewer patients. In this project, the research team did two studies:
- Study 1 looked at which traits put women at high risk for breast cancer so that clinics could schedule women with these traits first for exams in the future.
- Study 2 described the effects of the pandemic on women’s experiences with care and how clinics provided care.
What were the results?
Study 1. The study found that a small number of women, 3 percent, accounted for 25 percent of detected cancers. The research team classified these women as very high risk. Women at very high risk had:
- A lump or an abnormal mammogram
- A history of breast cancer, or were age 60 or older with no history of breast cancer
Women having their first mammogram were at very high risk of getting called back for another test.
Study 2. Women said they felt safe at screening exams during the pandemic. When deciding to get screening, women thought about:
- The risk of having cancer versus getting COVID-19
- The safety of screening
- How to get to visits
- Anxiety and fear due to screening
Women preferred to receive personal, clear, short, calm, and positive messages about screenings through mail, email, and patient portals.
At the onset of COVID-19, 97 percent of clinics reported closing or seeing fewer patients. By June 2020, clinics resumed care at the same level as before the pandemic. When seeing fewer patients, 96 percent of clinics rescheduled canceled screening exams first. Also, 93 percent scheduled tests to diagnose breast cancer before tests to screen for it.
What did the research team do?
Study 1. The research team used data from 92 clinics taking part in seven breast imaging registries across the country for:
- 854,230 women ages 18–89 to identify traits that increased the risk of a mammogram detecting cancer. Data were from January 2014 through December 2019.
- 925,777 women ages 18–89 to identify traits that increased the risk of getting called back for another test. Data were from January 2012 through December 2020.
Study 2. The research team held five focus groups with 30 women in seven states. The groups included women who did and didn’t have a history of breast cancer. The team asked about their experiences with tests to screen for or diagnose breast cancer during the pandemic. The team also surveyed 77 imaging clinics about the impact of the pandemic on care.
Women with breast cancer, doctors, and advocates gave input during the study.
What were the limits of the study?
Methods used for risk-based screening don’t consider patient preferences.
How can people use the results?
Breast imaging clinics can use the results when considering ways to schedule patients when fewer time slots are open.
Professional Abstract
In response to the COVID-19 public health crisis in 2020, PCORI launched an initiative to enhance existing research projects so that they could offer findings related to COVID-19. The initiative funded this study and others.
Background
During the COVID-19 pandemic, many breast imaging facilities closed temporarily. After reopening, facilities decreased patient services to minimize infection risk for patients and staff. Questions remain about which patients should receive services first when facilities offer limited services.
Objective
(1) To develop risk-based approaches to prioritize scheduling mammography services during reductions in capacity; (2) To describe women’s experiences with breast cancer imaging services during the pandemic; (3) To explore how COVID-19 affected breast imaging outcomes and facility operations
Study Design
| Design Element | Description |
|---|---|
| Design |
Observational study using registry data Descriptive study from focus groups and surveys |
| Population |
Observational study: Descriptive study: |
| Outcomes |
Observational study: Cancer detection rates; recall rates, defined as a mammogram interpretation that required additional imaging or evaluation Descriptive study: Patient experiences with breast cancer screening and facilities’ breast imaging practices during pandemic |
| Timeframe |
Observational study: Descriptive study: |
The observational study developed risk-based screening approaches to improve the likelihood of detecting cancer while performing fewer mammograms due to COVID-19. Researchers used breast imaging registry data from 92 imaging facilities participating in seven registries across the country. To estimate risk categories, researchers used statistical models to identify patient factors most strongly associated with cancer detection and recall.
The descriptive study examined women’s experiences with using imaging facilities and explored the impact of COVID-19 on imaging facility operations during the pandemic. Researchers conducted five virtual focus groups with 30 women from seven states. Groups included women with and without a history of breast cancer. Topics included decision making about breast cancer screening, information received about screening, and experiences with screening during the pandemic. To explore breast imaging practices, researchers surveyed 77 breast imaging facilities in six states.
Women with breast cancer, doctors, and advocates gave input during the studies.
Results
Risk-based screening. When determining risk categories for cancer detection with mammography, the study found that 3% of women accounted for 25% of detected cancers. Researchers categorized this group as very high risk. Women in this group had:
- Clinical indication of an abnormal mammogram or lump
- A history of breast cancer, or were age 60 or older with no history of breast cancer
Similarly, the 5% of screening mammograms classified as being at very high risk of recall accounted for 12% of recalled mammograms. Women having their first mammogram had very high recall rates.
Breast cancer diagnosis rates. Compared with March–September 2019, breast cancer diagnoses decreased by 24% in March–September 2020 (p<0.001).
Experiences using imaging facilities. Women reported feeling safe when receiving breast cancer screening during the pandemic. When deciding to proceed with screening, women considered:
- Risks of having cancer versus getting COVID-19
- Safety of screening
- Logistics and barriers
- General anxiety and fear of screening
Women preferred:
- Personalized communication
- Clear, concise, calm, and encouraging messages
- Multiple communication methods, including mail, email, and patient portals
Imaging operations. During the initial months of the COVID-19 pandemic, 97% of facilities reported closures or reduced capacity, with a rebound in services by June 2020. When services resumed, facilities prioritized scheduling canceled appointments first (96%) and diagnostic over screening tests (93%).
Limitations
Risk-based mammography algorithms do not consider individual preferences or worries about breast cancer.
Conclusions and Relevance
Prioritizing mammography for women at very high risk could improve the number of breast cancers detected during reductions in services. Personalized communication via multiple modes may help engage women in screening.
Peer Review Summary
The Peer-Review Summary for this COVID-19 study will be posted here soon.
Final Enhancement Report
This COVID-19 study's final enhancement report is expected to be available by April 2024.
Final Research Report
This project's final research report is expected to be available by April 2024.
Journal Citations
Results of This Project
Related Journal Citations
Peer-Review Summary
The Peer-Review Summary for this project will be posted here soon.