NATUROPATHIC DOCTOR IN ONTARIO
Breast Cancer Screening in Canada
Mammography, MRI, Ultrasound, Thermography, and Emerging Non-Invasive Tests
Breast Cancer Screening Tools
Breast cancer screening is intended to detect cancer before symptoms appear. The purpose is to identify disease at an earlier stage, when treatment options are broader and outcomes are generally better.
For a screening test to be recommended at the population level, it must demonstrate through high-quality studies that it reduces deaths from breast cancer and that its benefits outweigh potential harms.
In Canada, screening policies are determined at the provincial and territorial level, but recommendations are informed by national evidence reviews and expert panels. Several technologies are promoted to patients, including mammography, MRI, ultrasound, thermography, and newer biological tests such as the Auria tear-based assay. The strength of evidence supporting these approaches varies substantially.
Mammography in Canada: The Standard for Breast Cancer Screening
Mammography uses low-dose X-ray imaging to detect abnormalities in breast tissue. It is currently the only screening method that has consistently demonstrated a reduction in breast cancer mortality in large randomized controlled trials.
Canadian recommendations are guided by the Canadian Task Force on Preventive Health Care. Provincial programs also align with evidence assessed by agencies such as Health Canada.
Most organized screening programs in Canada invite women between the ages of 50 and 74 for routine mammography, typically every two to three years. Some provinces allow screening starting at age 40, either by self-referral or program expansion. Policies continue to evolve.
Benefits of Mammography
Earlier detection of invasive cancers
Demonstrated reduction in breast cancer mortality at the population level
Limitations of Mammography
False-positive findings leading to additional imaging or biopsy
Reduced sensitivity in dense breast tissue
Small radiation exposure
Despite these limitations, mammography remains the standard screening tool for women at average risk.
Breast MRI: High-Sensitivity Screening for High-Risk Women
Magnetic resonance imaging (MRI) uses magnetic fields and contrast material to generate detailed images of breast tissue. MRI is more sensitive than mammography and is particularly useful in women with dense breasts or elevated genetic risk.
In Canada, MRI screening is generally recommended for women at high risk, including those with confirmed BRCA1 or BRCA2 mutations or a strong family history. It is used in addition to mammography rather than as a replacement.
Benefits and Limitations of Breast MRI
MRI detects more cancers but also has higher false-positive rates and higher cost. For this reason, it is not used for routine screening in average-risk women.
Breast Ultrasound: Supplemental Screening for Dense Breasts
Ultrasound imaging uses sound waves rather than radiation. It is commonly used to evaluate specific abnormalities identified on mammography or physical examination. It may also be used as supplemental screening in women with dense breasts.
Current evidence does not show that ultrasound alone reduces breast cancer mortality when used as a primary screening tool. While it can detect additional cancers—especially in dense tissue—it also increases the rate of false-positive findings.
Ultrasound is therefore considered a complementary tool rather than a standalone screening method.
Thermography for Breast Cancer Screening: What Does the Evidence Say?
Thermography uses infrared cameras to measure surface heat patterns on the breast. The underlying theory is that tumors may produce increased blood flow and higher temperatures.
However, thermography has not demonstrated a reduction in breast cancer mortality in high-quality clinical trials. Regulatory authorities, including Health Canada and the U.S. Food and Drug Administration, have indicated that thermography should not be used as a substitute for mammography.
Evidence shows that thermography may miss cancers and may produce false reassurance if used alone.
No major Canadian guideline body recommends thermography as a primary breast cancer screening tool.
Auria Tear Test and Emerging Blood-Based Screening Tests
The Auria test is not a blood test. It is a tear-based biomarker assay that analyzes proteins collected from a tear sample. The company describes it as a biological screening tool that may indicate elevated risk markers associated with breast abnormalities. It is intended to supplement—not replace—imaging-based screening.
At present, there are no large, independent randomized trials demonstrating that the Auria test reduces breast cancer mortality. It is not included in recommendations from the Canadian Task Force on Preventive Health Care or provincial screening programs.
Similarly, blood-based multi-cancer early detection tests that analyze circulating tumor DNA are under investigation. These tests are promising from a research perspective, but they have not yet demonstrated population-level mortality benefit for breast cancer and are not recommended as substitutes for mammography.
Weighing the Benefits and Risks of Breast Cancer Screening
Screening decisions involve trade-offs.
Potential Benefits
Earlier detection
Reduced mortality
Potential Harms
Overdiagnosis
False positives
Unnecessary biopsies
Anxiety
Cost
Because screening is offered to healthy individuals, a high standard of evidence is required before recommending widespread use.
What Is Currently Recommended for Breast Cancer Screening in Canada?
In Canada:
Mammography remains the only screening modality with strong evidence of mortality reduction in average-risk women.
MRI has a defined role for high-risk populations.
Ultrasound is used as a supplemental tool.
Thermography and tear- or blood-based commercial tests such as Auria do not currently have sufficient evidence to replace established screening methods.
Patients are encouraged to discuss their individual risk factors—including family history, genetic background, prior chest radiation, breast density, and personal values—with a qualified health professional. Screening recommendations may differ based on age and province of residence.
As research advances, new technologies may eventually reshape screening strategies. Until high-quality evidence demonstrates clear benefit, established imaging-based screening remains the foundation of breast cancer detection efforts in Canada.
Still not clear about how to best manage your breast health? Book a 1-on-1 appointment to review your particular case in detail, and together we can come up with a curated plan to make sure you stay healthy.
Dr. Mariia Tanasyshyn, Naturopathic Doctor
Dr. Mariia Tanasyshyn, ND, is a licensed Naturopathic Doctor in Ontario with a rare and valuable dual background. Before completing her naturopathic medical training at the Canadian College of Naturopathic Medicine, Dr. Mariia earned her Doctor of Medicine (MD) degree in Ukraine, where she trained extensively in internal medicine. Although she is not practicing as a medical doctor in Ontario, her medical education provides a deep understanding of complex health conditions and allows her to interpret symptoms, labs, and diagnoses through a uniquely integrative lens.
Now fully licensed as a naturopathic doctor (ND) under the College of Naturopaths of Ontario (CONO), she offers evidence-informed, patient-centered care that blends the strengths of both medical and naturopathic approaches. Her visits are not covered by OHIP, but may be reimbursed through extended health insurance like other naturopathic services.
Dr. Mariia is passionate about helping patients feel heard, informed, and empowered. She prioritizes clear communication, shared decision-making, and creating personalized treatment plans that meet her patients where they are.
Patients often seek out Dr. Mariia when they are looking for health care answers and support. These patients often don’t have access to a family doctor, or they are receiving inadequate care from their GP.
Fluent in English, Ukrainian, and Polish, Dr. Mariia is committed to accessible, compassionate care for individuals and families across Ontario through secure virtual visits.
