Many of my patients have asked me the differences between the types of imaging that is used for breast cancer screening, so in keeping with Breast Cancer Awareness Month, I believe this is an extremely important topic to discuss. Out of these 3 imaging techniques, the ONLY one that has been shown to be the most effective is the MAMMOGRAM, which is an x-ray of the breast tissue. One of the main concerns that I hear most often (apart from it being extremely uncomfortable) is the exposure to radiation (x-rays). Even though women are being exposed to a low dose of radiation, in medicine, every recommendation and decision is be based on a consideration of benefit vs. harm. In this case, the benefit of women going for routine breast mammograms is higher than the amount of harm that may be caused from a low dose of radiation in that session. In Ontario, women who are not at a higher risk of breast cancer are recommended to start their screening mammograms at age 50 and every 2 years thereafter.
Magnetic Resonance Imaging (MRI), unlike mammograms, DO NOT use radiation to produce the images so there is no radiation exposure in this imaging procedure. MRI is only incorporated into breast cancer screening for individuals who are at high risk for breast cancer (for example, strong family history, mutation of a BRCA gene, chest radiation under age 30). In this patient population, both mammograms and MRIs are used for screening. Even though MRIs are more sensitive to lesions, the flip side of this is that there will be increased FALSE positives (thinking something is there when it actually isn’t). Research shows that when there is an increase in false positives, there’s increases in unnecessary procedures, such as biopsies, and distress that may negatively impact an individual’s quality of life. Furthermore, MRIs are extremely more expensive in terms of machinery and they take significantly longer to run compared to an x-ray. Using MRIs as a screening method for ALL individuals would neither be cost nor time-efficient.
Breast thermography has been touted to be a non-invasive thermal imaging “alternative” to the mammogram because of the lack of radiation. Thermography measures blood flow (thereby measuring temperature) using an infrared camera. The theory behind thermography and breast cancer is that cancerous cells have increased blood flow which can be seen using the infrared camera as “hot spots”. However, this HAS NOT shown to be as sensitive as the mammogram for detecting breast cancer. There are some businesses and private clinics that are using this to promote breast health but it is extremely important that women understand that this tool is NOT a validated tool for detecting breast cancer and should not be promoted as such.
IN CONCLUSION // Mammograms are currently the only validated imaging tool to effectively screen for breast cancer. While MRIs are used in conjunction with mammograms in women who are at an increased risk of beast cancer, they are not often used in the general screening. Finally, as of now, breast thermography does not show to be as effective or sensitive for breast cancer as mammograms.