Reviewed and updated by Myrna Buiser Schnur, MSN, RN: February 13, 2024
According to the National Cancer Institutes’ (2023) latest statistics, approximately 2,261,420 new cases of breast cancer were diagnosed worldwide in 2020. While research has made great progress around treatment, the best strategy to improve breast cancer survival rates is to catch it early before it has metastasized. Screening plays a significant role in my annual health care routine due to my strong family history of breast cancer. My primary care providers and specialists recommended that I obtain a breast magnetic resonance imaging (MRI) each year, alternating every 6 months with routine mammography. In talking with my two sisters, I discovered that they were being given different advice on screening from their health care providers. In addition, the guidelines vary among several leading societies regarding the methods, frequency, and age to begin initial screening causing great confusion for patients and debate among the medical community. I’ve attempted to provide a simplified summary of the screening guidelines in this blog.
Screening Methods (Elmore, 2024)
First, let’s briefly review the screening methods that are available today.
- Mammogram (Digital 2-dimensional [2D] or film): remains the standard imaging tool used to detect breast cancer in average-risk women. Studies support this method which has been shown to decrease cancer-related mortality (Slanetz & Lee, 2023). However, mammography may miss up to 20% of underlying breast cancers.
- Screening mammogram: performed in women with no clinical symptoms or complaints.
- Diagnostic mammogram: performed in women who have breast symptoms (palpable lump, nipple discharge, or focal pain) or a prior abnormal screening mammogram (mass, calcification, or asymmetry).
- Surveillance mammogram: performed in women who have a history of breast cancer.
- Digital breast tomosynthesis (DBT): also known as 3D mammography, a series of mammograms are taken at various angles and compiled to create a 3D image; radiation dose is higher; it may detect more cancers with a lower false positive rate (Slanetz & Lee, 2023). It is also recommended for women with dense breast tissue due to its higher sensitivity. However it is is more expensive than a conventional mammogram and may not be covered by insurance.
- Whole breast ultrasound (WBUS): not typically used for routine screening in women with average risk; may detect early-stage cancers not found on mammogram, specifically in women with dense breast tissue; often yields false-positive results. Ultrasound may be used as a diagnostic tool following an abnormal mammogram to determine if a mass is solid, filled with fluid, or a combination of both.
- Magnetic resonance imaging (MRI): not recommended for average-risk women. MRI in combination with mammography is used primarily to screen high-risk patients with greater than 20 percent lifetime risk.
- Clinical breast exam (CBE): performed by a trained health care provider, the clinical physical exam is important to evaluate breast complaints or abnormalities but is not recommended as part of the screening process for average-risk women as it may increase false-positive rates. However, CBE plays an important role in areas where imaging is not widely available.
- Breast self-exam (BSE): education on breast self-examination has not shown to improve mortality, rather it has increased the number of benign breast biopsies. Advocate for breast self-awareness and instruct patients to note any changes in their bodies and discuss them with their health care provider.
- New Imaging Technologies: other supplemental screening tools are being developed but are not routinely used in clinical settings. These include molecular breast imaging and an abbreviated breast MRI exam called first post-contrast acquisition subtracted (FAST) MRI protocol (Freer & Slanetz, 2023).
Risk Profile
Screening method and frequency are determined by a patient’s risk profile. There are several tools available to estimate a woman’s risk for developing breast cancer. The
National Cancer Institute’s Breast Cancer Risk Assessment Tool or Gail Model is used for women who have never had a diagnosis of breast cancer and who do not have a strong family history. For women with a strong family history of breast cancer (more than two first-degree relatives with breast cancer), familial risk assessment tools will help identify women who need genetic counseling and/or
genetic testing. These include
Ontario Family History Risk Assessment Tool,
Manchester Scoring System,
Referral Screening Tool,
Pedigree Assessment Tool,
7-Question Family History Screen,
International Breast Cancer Intervention Study Model, and
BRCAPRO (Slanetz & Lee 2023).
Major factors that determine risk category include (Elmore, 2024):
- Personal history of breast, ovarian, tubal, or peritoneal cancer
- Family history of breast, ovarian, tubal, or peritoneal cancer
- Ancestry (i.e., Ashkenazi Jewish) associated with BRCA1 or BRCA2 mutations
- Carrier of pathogenic mutation for hereditary breast and ovarian cancer (self or relative)
- Breast density, based on mammogram
- Previous breast biopsy indicating high-risk lesion (i.e., atypical hyperplasia)
- Age of menarche, age at first live birth, number of pregnancies, and menopausal status
- Radiotherapy to the chest between age 10 and 30 years
Screening Recommendations
Screening recommendations are based on an individual’s lifetime risk of being diagnosed with breast cancer (not “dying” from breast cancer) (Elmore, 2024). Below is a summary of the frequency of mammography and supplemental screening recommendations as outlined in the latest guidelines from the
American Cancer Society (ACS) (2023),
U.S. Preventative Services Task Force (USPSTF) (2023), and version 3 of the
National Comprehensive Cancer Network (NCCN) (2023).
| Breast Cancer Screening Recommendations |
| |
Average Risk
(<15%) |
Moderate Risk
(15 – 20%) |
High Risk
(>20%) |
| Risk Factors |
None of the major risk factors listed above. |
- Personal or family history of breast cancer in a first-degree relative but no known genetic syndrome
- Extremely or heterogeneously dense breast tissue, per mammogram
|
- Known BRCA or other genes
- History of chest radiation prior to age 30
- Atypical hyperplasia
- Calculated lifetime risk of developing breast cancer greater than 20%
|
Frequency of mammogram
(Baron et al., 2018) |
Based on age and breast density:
- Under age 40: screening not recommended
- Age 40-44: every one to two years or at discretion of patient
- Age 45-54: annually (ACS)
- Age 55-74: every one to two years (ACS, NCCN, USPSTF)
- Age 75 and older: based on clinical judgment (NCCN) and if life expectancy is at least 10 years
|
- Annual mammogram with tomosynthesis beginning 10 years prior to when youngest family member was diagnosed with breast cancer or at age 40 (whichever comes first) (NCCN, 2023)
- Refer to a high-risk screening clinic for evaluation, increased surveillance, possible genetic testing, and risk reduction treatment (i.e., chemoprevention and prophylactic surgery).
|
| Supplemental screening with MRI or ultrasound |
Not recommended; limited evidence that MRI or ultrasound in addition to mammography provide additional benefit (USPSTF). |
Discuss with patient their personal preferences, risks versus benefits, insurance coverage and availability of imaging method. No recommendation for or against annual MRI (ACS, NCCN). |
Annual supplemental breast MRI with and without contrast to begin 10 years prior to when the youngest family member was diagnosed with breast cancer, (not prior to age 25) or begin at age 40 (whichever comes first) (NCCN, 2023). |
*Note this table reflects a basic summary of the recommendations. Please refer to the complete guidelines for full details.
Breast Tissue Density (Freer & Lanetz, 2023)
Breast tissue density is commonly categorized using the American College of Radiology’s Breast Imaging Reporting and Data System classification system:
- A – Breasts are almost entirely fatty
- B – Scattered areas of fibroglandular density
- C – Heterogeneously dense (may hide small masses)
- D – Extremely dense (decreases the sensitivity of mammography)
Approximately 50% of women in the U.S. age 40-60 have dense breast tissue (either heterogeneously or extremely dense) which is associated with an increased risk of breast cancer but not an increased risk of death due to breast cancer. Digital mammography (2D or 3D tomosynthesis) is the preferred method for screening over film mammography. Several states have passed legislation mandating that health care providers notify women about breast density on their mammogram reports. Some states have also required these include recommendations for supplemental screening (i.e., ultrasound and MRI) for women with dense breast tissue as it may interfere with cancer detection. For average-risk individuals, ultrasound or MRI are options, however insurance may not cover these additional costs (Elmore, 2024).
Potential Risks Related to Screening
As with any medical test or procedure, there are risks associated with breast cancer screening which include (Elmore, 2024):
- False positive results which may lead to unnecessary biopsy procedures and treatments
- Overdiagnosis (disease is found on screening, however it wouldn’t have caused morbidity or mortality if it had not been found) which may result in unnecessary chemotherapy or surgery
- Patient anxiety and stress related to both false positive results and overdiagnosis
- Exposure to radiation; risk is generally low, however it may be harmful in women with BRCA1 or BRCA2 mutations
- Exposure to intravenous contrast during MRI
- Discomfort during the procedure
Special Considerations (Elmore, 2024)
- Breast augmentation/implants: Patients who have had breast augmentation with implants require routine screening mammography with the same frequency as individuals without implants. Note that implants may be radiopaque and can conceal small lesions and may make breast compression difficult.
- Mastectomy with or without breast reconstruction: mammography is not routinely performed following mastectomy when no native tissue remains. Physical exam is the preferred screening method for breast reconstruction patients.
- Pregnancy: screening mammography is not routinely performed.
- Biological males: routine screening is not performed unless they are carriers of BRCA1/2, and who have evidence of gynecomastia or parenchymal/glandular breast density.
- Recent COVID-19 vaccination: COVID-19 mRNA vaccines may cause temporary swelling of axillary lymph nodes, affecting the interpretation of the mammogram. Despite this, research found mammography should not be delayed based on COVID vaccine timing.
Conclusion
Shared decision-making should be used to determine if and which methods of breast cancer screening will be utilized. It is important for all clinicians to understand the current recommendations and to talk to their patients about their individual preferences for screening. Every patient has a unique history and profile, and each must take into consideration the risks versus benefits. There is no one strategy that fits all, however the better informed you are, the better advice and guidance you can provide to your patients.
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