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Know Your Breasts: Understanding Breast Cancer Screening


doctor pointing at a mammogram image
Know Your Breasts: Understand Breast Cancer Screening

Today we're diving into a topic that's both timely and important: breast cancer screening. In honor of breast cancer awareness month, I wanted to shed some light on this important part of your proactive breast health. I want you to consider your familiarity with breast cancer screening, why we do it, your options, and understanding your results. If you think some clarity might be helpful, you are in the right place! We're bringing out the big words, breaking them down, and as always, I will do my best to make it all digestible and approachable. So, grab your favorite beverage, and let's get into it!



The Big Picture

Breast cancer is a subject that affects most of us, directly or indirectly. Did you know that about 1 in 8 Canadian women will develop breast cancer during their lifetime(Canada 2017)? Yep, you read that right. Among women breast cancer is the most common cancer diagnosis (Canada 2017). Now for the good news… breast cancer survival rates are high and improving! 82% of female breast cancer is caught early in stage I or II and the 5-year survival rate for breast cancer in Canada is 88% (Canada 2017).

Canada has had breast screening protocols in place in most regions of Canada since the early 1990s. During this time we have seen a substantial decrease in breast cancer mortality “from 41.7 per 100 000 in 1988 to an estimated 23.2 per 100 000 in 2017” (Klarenbach et al. 2018). This improvement is thought to reflect advancements in breast cancer treatment and earlier detection of breast cancer from breast screening programs (Klarenbach et al. 2018). This is a huge win in the cancer world and the reason we continue to place emphasis on screening. Let’s now turn our attention to breast screening in Alberta. To better understand your recommended screening, you must first understand your risk.



Know Your Breast Risk, Be Your Own Hero

There are differences among Canadian, European, and American breast cancer screening recommendations, but for the purposes of this article, we will be sticking to Canadian and Albertan recommendations.


High Risk vs. Average Risk: Knowing your risk level is of utmost importance in breast cancer screening as this plays a large role in determining your screening recommendations. High-risk individuals are those with gene mutations like BRCA1 or BRCA2, a personal or first-degree relative with a history of breast cancer or breast cancer gene mutations, or those who have had chest radiation therapy before the age of 30 or within the last 8 years (Canada, 2017). For these individuals, screening recommendations differ. High-risk individuals are advised to undergo screening biannually and to begin their screening earlier. The most common recommendation is that these women start their screening at age 30 and have both a mammogram and breast MRI (staggered by 6 months) annually. Specific recommendations will be provided by the specialist assigned to your case. If you are at high risk of breast cancer and have not been referred to a specialist, it is time to talk to your family doctor about a referral. In Edmonton, we are lucky to have the dedicated individuals at the Allard Hereditary Breast and Ovarian Cancer Clinic at the Louis Hole Women’s Hospital.

If you do not fall into the high-risk group, congratulations! For you, the Alberta guidelines are as follows (“Breast Cancer Screening” n.d.):

  • For women between the ages of 40-44 years old, mammograms are not recommended. If you feel that you should be screened during this time, you can talk to your doctor about breast screening(“Breast Cancer Screening” n.d.).

  • For women between the ages of 45-74 years old, mammograms are recommended every two years(“Breast Cancer Screening” n.d.).

  • For women 75 years and older, whether or not you continue with breast cancer screening should be a decision made with your health care provider(“Breast Cancer Screening” n.d.).



The ABCs of Breast Cancer Screening Tools

Let's dig a bit deeper into the types of screening tests available, shall we?


Mammography:

This is to date the gold standard for breast cancer screening. It uses X-rays taken at 2 different angles to provide images of the breast. These images are then examined for any suspicious lumps or abnormalities. Mammogram images are very good at detecting abnormalities that are too small to be seen or felt in the imaged breast tissue.

There are 2 main concerns voiced with regard to mammograms: first, they are uncomfortable, and second, they expose women to radiation. Unfortunately, there is no way around the breast compression with a mammogram. Some mammogram techs are gentler than others. I would encourage you to work with the technician facilitating your mammogram. Ask them to be gentle and how best to work together to make the procedure as comfortable as possible. As for the second concern, radiation exposure, it is true that you are exposed to x-ray radiation during this procedure. I would like to provide some context to better understand this and to help guide your decision about mammograms. The Canadian Nuclear Safety Commission outlines radiation exposure from various day-to-day activities and from various medical tests. You can check it out here: https://nuclearsafety.gc.ca/eng/resources/infographics/di-ir/index.cfm I found this very interesting! For reference, the average dose of radiation from a mammogram is 0.42 mSv (Safety Commission 2016). Did you know that the average dose of radiation you get from your food alone is 0.29 mSv per year and the average dose from the sun is 0.32 mSv per year (Safety Commission 2016) ??? The CNSC also lists the lowest acute dose of radiation found to cause damage to tissues or organs as 100 mSv (Safety Commission 2016). In medicine we are constantly weighing the pros and cons and radiation exposure from mammography is no different. In 2021 Hooshmand et al. conducted a review of the scientific literature to better understand mammography risk; they determined that the average screening radiation exposure for women of average risk screening from the age of 40-74 years old would result in 65 radiation-induced cancers and 8 deaths per 100,000 women (Hooshmand et al. 2022). They also determined that this translated to 62 lives saved from screening for every 1 death from mammogram radiation exposure-induced cancers (Hooshmand et al. 2022). It is important that you understand this radiation risk and make a choice that feels right for you. Hopefully, this is helpful for your decisions about mammograms. Only you can make the decision about what level of risk you are comfortable with, I would encourage you to weigh this for yourself. If you have more questions or are unsure have a discussion with your healthcare provider, we are here to help.

If you decide to proceed with your recommended mammograms, I encourage you to request a lead apron and thyroid shields during the procedure to limit your radiation exposure. The lead apron is a must if you are within your childbearing years to protect your ovaries (eggs) and I would highly recommend them if you belong to the high-risk group due to the increased frequency of screening that is recommended.


Thermography:

Breast thermography is the newer kid on the block. It uses infrared imaging to detect heat patterns and blood flow in body tissues. When cancer is growing it will most often induce a process called angiogenesis, which is the induction of growth of new blood vessels; this causes these malignancies to show up as “hotter” in the thermal images. The positives to this test are that there is no radiation, and it is non-invasive. This test does require that you sit topless in a cold room with the technician for 30-45 min while the images are being generated; this is a bit uncomfortable, but not terrible. There are issues to consider with the results of this test however, thermography is not very specific. This means that there are a number of reasons that different areas of the breast might appear warmer, and this can lead to a lot of false positive results. (A false positive is when a test indicates a positive (problem) result when there is no cause for concern). In these cases, the recommendation would be to do a follow-up mammogram and/ or ultrasound. For you, this means more testing, and as you might expect can lead to anxiety/ worry while you are waiting for the follow-up imaging. Further, early on in their development cancers do not stimulate angiogenesis (Madu et al. 2020). Currently, the Canadian guidelines recommend against using thermography as a screening tool for these reasons (Klarenbach et al. 2018); but the last systematic review on this topic was done over a decade ago (Fitzgerald and Berentson-Shaw 2012) and new work is now looking at improving the accuracy by combining these results with machine learning (Singh and Singh 2020). Will there be a change in the guidelines? Only time will tell.

Another consideration is that breast thermography is not covered by provincial health care plans and will come at an additional cost to you unless you have coverage by a private insurance plan. All of the other breast screening imaging tests mentioned here are covered by provincial health care.


Self Breast Exam:

The current Canadian guidelines recommend against self-breast exams as the evidence does not support this recommendation (Klarenbach et al. 2018). As with other recommendations, this is not consistent among countries with national breast screening programs. What does seem to be consistent is the collective agreement that teaching breast awareness is beneficial and empowering. Having a general understanding of what your breasts feel like normally and reporting any changes you feel to your doctor is important. For more information about what you are looking for, have a read through this article: https://www.mdanderson.org/publications/focused-on-health/breast-cancer-symptoms-you-shouldn-t-ignore.h10-1592991.html If you would like to know more about this let me know, I would be happy to write about this in the future. For more immediate questions, your healthcare provider is available and happy to help.


Magnetic Resonance Imaging (MRI):

In this procedure, a dye containing gadolinium is given intravenously while you are in a device with a large and powerful rotating magnet. This technique allows us to get clear pictures of soft tissues. This type of imaging is not recommended for screening women of average risk as it is much more costly and more invasive (Klarenbach et al. 2018). Also, gadolinium can have side effects, and special precautions are required for those with kidney pathologies. MRI is, however, part of the general screening recommendations for high-risk women(Klarenbach et al. 2018).


Ultrasound:

This procedure uses high-frequency sound waves to produce images. This test uses no radiation and is relatively non-invasive, so has been of interest for use as a screening tool. Due to the safety profile, it is also the imaging method of choice for women who are pregnant or nursing (“Breast Ultrasound & ABUS Breast Imaging in Alberta | Insight Medical” n.d.)

It is important to understand the difference between diagnostic breast ultrasound in which an ultrasound technician uses a handheld wand to complete the test. This “typical” form of ultrasound is well suited to examining small areas or suspicious areas identified by other imaging methods or masses identified in the underarm area. This type of ultrasound is not ideal as a screening tool for the entire breast area as it relies heavily on the skill of the technician and takes a long time to complete (there is a lot of tissue to cover). Like thermography this test requires extended periods in which you are disrobed with a technician; the room, however, is not chilled, and the ultrasound gel is heated, which is a nice touch.

There is a relatively new ultrasound tool called Automated Breast Ultrasound or ABUS which is an automated ultrasound that uses a larger probe and can take hundreds of thin images of the breast at a time, providing 3D images instead of the 2D images typically produced with regular ultrasound. Because the procedure is automated it also takes a lot less time (typically only 20-30 min), it decreases operator dependence, and is able to produce highly reproducible results (Boca (Bene) et al. 2021). ABUS has now been adopted as part of our regular screening for women with dense breasts in Alberta. Mammogram images are difficult to interpret for women with dense breasts and ABUS imaging is typically recommended in combination with mammograms for women with dense breast tissue (“Breast Ultrasound & ABUS Breast Imaging in Alberta | Insight Medical” n.d.). We will circle back to breast density again in a moment.

Another final use for ultrasound that I would like to mention is to help guide biopsies. If a specious mass is found and biopsy is recommended, the doctor performing your biopsy will most often use ultrasound to provide real-time images to ensure that they are sampling tissue from the correct area in your breast.



Results and Callbacks

It is common to get a call back after your screening test. Don’t panic! The most common reason for callbacks is to inform you that you should return to or keep up with your regular screening schedule. Sometimes the technician is not able to get clear pictures and needs to repeat the test or they might recommend a breast ultrasound to confirm findings. They may recommend that you come back in 6 months for additional testing. If you are found to have dense breast tissue you will be placed into a different screening category and your regular screening schedule modified to include more imaging. Finally, if a suspicious mass is found they will recommend a biopsy of the suspicious area. These recommendations are determined based on the BiRADS Score; let’s dive into this next.


Deciphering the Results: BiRADS Scoring

The Breast Imaging-Reporting and Data System (BiRADS) is a standardized scoring key put forth by the American College of Radiology; it is basically the Rosetta Stone for interpreting mammogram results used by most countries with breast screening programs. It helps radiologists and doctors to understand a person’s risk of cancer and what the best next steps for evaluation are (Bittner 2010). Scores range from 0 (Incomplete), 1 (Negative For Malignancy), all the way to 6 (Known Biopsy—Proven Malignancy). In addition to the number rating, you will see a letter A-D rating; this is reporting on your breast density. It is harder to see malignancies in dense breast tissue AND people with dense breasts are at higher risk of developing breast cancer (“Home - Dense Breasts Canada” n.d.). People with a breast density of C or D will be followed more closely and additional imaging will be recommended as previously discussed. Please understand that breast density is not dependent on breast size but instead on the ratio of glandular to fatty tissue in the breast. If you have dense breasts, you are not alone; you are among the 43% of women over the age of 40 who have a breast density of C-D (“Home - Dense Breasts Canada” n.d.). You will also be interested to know that in Alberta, since 2020, it is mandatory that you receive notice about your breast density following your mammogram. I hope this has helped you to feel more empowered to understand your results; no longer will they simply be filed away never to be looked at again.



The Power is Yours

Information is power, and the more you know, the better you can advocate for your own health. I know that making decisions about protecting your future health can be overwhelming and intimidating; know that you are not alone. If you are unsure, ask questions, if you are still unclear ask again, but don’t get stuck in moving forward because you are unclear. Of course, we are always here to help as well. Be informed. Be proactive.



The Takeaway

  1. Breast cancer affects a lot of people, and survival rates are high and improving.

  2. Knowing your risk level and breast density will guide your screening strategy.

  3. There are different types of screening methods, each with its own pros and cons.

  4. Early detection is critical to cancer outcomes and regular screening is the best way to find potential cancers early.

  5. BiRADS scoring provides a standardized way to interpret mammogram results.

  6. Be informed. Be proactive.

So, go ahead, take charge of your health, and let’s tip the odds in your favor!




References

  1. Bittner, Rebecca B. 2010. “Guide to Mammography Reports: BI-RADS Terminology.” American Family Physician 82 (2): 114–15.

  2. Boca (Bene), Ioana, Anca Ileana Ciurea, Cristiana Augusta Ciortea, and Sorin Marian Dudea. 2021. “Pros and Cons for Automated Breast Ultrasound (ABUS): A Narrative Review.” Journal of Personalized Medicine 11 (8): 703. https://doi.org/10.3390/jpm11080703.

  3. “Breast Cancer Screening.” n.d. Accessed September 25, 2023. https://myhealth.alberta.ca:443/Health/Pages/conditions.aspx?hwid=tv8455.

  4. “Breast Ultrasound & ABUS Breast Imaging in Alberta | Insight Medical.” n.d. Insight Medical Imaging (blog). Accessed October 6, 2023. https://x-ray.ca/services/breast-screening/breast-ultrasound/.

  5. Canada, Public Health Agency of. 2017. “Breast Cancer.” Education and awareness. September 27, 2017. https://www.canada.ca/en/public-health/services/publications/diseases-conditions/breast-cancer.html.

  6. Fitzgerald, Anita, and Jessica Berentson-Shaw. 2012. “Thermography as a Screening and Diagnostic Tool: A Systematic Review.” The New Zealand Medical Journal 125 (1351): 80–91.

  7. “Home - Dense Breasts Canada.” n.d. Accessed October 2, 2023. https://densebreastscanada.ca/, https://densebreastscanada.ca/.

  8. Hooshmand, Sahand, Warren M. Reed, Mo’ayyad E. Suleiman, and Patrick C. Brennan. 2022. “A Review of Screening Mammography: The Benefits and Radiation Risks Put into Perspective.” Journal of Medical Imaging and Radiation Sciences 53 (1): 147–58. https://doi.org/10.1016/j.jmir.2021.12.002.

  9. Klarenbach, Scott, Nicki Sims-Jones, Gabriela Lewin, Harminder Singh, Guylène Thériault, Marcello Tonelli, Marion Doull, Susan Courage, Alejandra Jaramillo Garcia, and Brett D. Thombs. 2018. “Recommendations on Screening for Breast Cancer in Women Aged 40–74 Years Who Are Not at Increased Risk for Breast Cancer.” CMAJ 190 (49): E1441–51. https://doi.org/10.1503/cmaj.180463.

  10. Madu, Chikezie O., Stephanie Wang, Chinua O. Madu, and Yi Lu. 2020. “Angiogenesis in Breast Cancer Progression, Diagnosis, and Treatment.” Journal of Cancer 11 (15): 4474–94. https://doi.org/10.7150/jca.44313.

  11. Safety Commission, Canadian Nuclear. 2016. “Diagnostic Imaging and Ionizing Radiation.” February 29, 2016. https://nuclearsafety.gc.ca/eng/resources/infographics/di-ir/index.cfm.

  12. Singh, Deepika, and Ashutosh Kumar Singh. 2020. “Role of Image Thermography in Early Breast Cancer Detection- Past, Present and Future.” Computer Methods and Programs in Biomedicine 183 (January): 105074. https://doi.org/10.1016/j.cmpb.2019.105074.





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