The Importance of Screening

Screening imaging exams are important to help detect diseases early while they can still be successfully treated.

Screening is different from diagnostic medical imaging. Diagnostic exams are performed when you have symptoms, to identify a cause, or if your doctor has discovered an abnormality. Examples include X-ray to identify a broken bone or an obstetrical ultrasound to confirm a pregnancy.

Screening exams, on the other hand, are performed to help detect diseases early, before they cause symptoms. Typically, a screening exam is performed at a regular interval, such as annually. One of the most common examples of screening is mammograms performed to look for subtle changes in your breast tissue which may reflect an early cancer.

Making screening a part of your health care regimen ensures diseases are found early, when they are still treatable. Screening saves lives. According to the Canadian Cancer Society, the death rate from breast cancer has been declining since the 1980s. This is thanks to earlier detection from regular mammogram screening and improvements in breast cancer treatment.

TYPES OF SCREENING EXAMS

Screening mammography can be requested for women aged 40 and above when there are no symptoms, as part of a breast screening program. Mammography is a type of X-ray exam that takes images – called mammograms – for a detailed look at the internal structure of breast tissue to see changes that are too small for you or your doctor to feel. Having a screening mammogram every year, or every two years, makes it easier for a radiologist to compare your images and see changes or areas of concern. As part of the Alberta Breast Screening program, women 50 years and older don’t need a referral from a doctor to have a mammogram.

Bone mineral densitometry (BMD) is another type of medical imaging screening exam. BMD is an X-ray that takes very precise measurements of your bone density to help measure bone loss and your risk of developing osteoporosis. Low bone density and osteoporosis rarely have symptoms so may not be discovered until you sustain a fracture. According to Osteoporosis Canada, 80 per cent of all fractures in people 50 years of age or older are caused by osteoporosis. In Alberta, a first (baseline) BMD exam might be recommended between ages 50-65 – your doctor will examine your risk factors before determining when to request this exam. Subsequent exams would then be performed every 1-5 years depending on your risk level and previous BMD results.

Screening exams can also be performed for early detection of heart disease, colon cancer, or lung cancer. Patients who are at high risk of these illnesses due to a family history of disease or personal risk factors can have CT screening. These tests are often performed with a low radiation dose and can identify these diseases while they are still treatable. For example, the NELSON trial in Belgium and the Netherlands in 2018 concluded that CT screening of men at high risk for lung cancer reduced lung cancer deaths by an overall percentage of 26% after 10 years.

HOW DO I GET A SCREENING EXAM?

Except for breast screening in women over 50, both screening and diagnostic imaging exams must be requested by a health care practitioner. Which type of imaging is appropriate will depend on your medical and family history, risk factors, and any relevant symptoms.

At Mayfair Diagnostics the majority of our services are available through the Alberta or Saskatchewan health care insurance plans. BMD and mammography screening exams are covered under provincial health care plans. Your doctor will consider your age, gender, and risk factors when recommending whether you would benefit from regular screening, and how often. Read more about the Alberta and Saskatchewan breast screening guidelines, and national BMD guidelines.

We also offer private CT and MRI services, similar to that offered in hospitals in the public health care system. This includes CT screening exams, such as a low dose virtual colonoscopy to screen for colon cancer, a low-dose chest CT to screen for early signs of lung cancer, or a coronary CT angiography to screen for plaque in the arteries supplying the heart muscle (a risk factor for heart disease). These exams are available as private pay exams and can be purchased for single or multiple body areas, or as a Health Assessment Package.

For more information, please visit our services page.

REFERENCES

Alberta Health Services (2019) “Get Screened.” www.screeningforlife.ca. Accessed July 10, 2020.

Canadian Cancer Society (2018) “Breast Cancer Statistics.” www.cancer.ca. Accessed July 6, 2020.

Canadian Cancer Society (2020) “Bone density scan.” www.cancer.ca. Accessed July 6, 2020.

Engmann et al. (2017) “Population-Attributable Risk Proportion of Clinical Risk Factors for Breast Cancer.” JAMA Oncology. 2017; 3(9) 1228-36.

IASLC 19thWorld Lung Conference on Lung Cancer. NELSON Study Shows CT Screening for Nodule Volume Management Reduces Lung Cancer Mortality by 26 Percent in Men. Press Release. September 25, 2018.

National Osteoporosis Foundation (2020) “What is Osteoporosis and What Causes It?” www.nof.org. Accessed July 6, 2020.

Osteoporosis Canada (2020) “Fast facts.” www.osteoporosis.ca. Accessed July 6, 2020.

Osteoporosis Canada (2020) “Why should I get tested?” www.osteoporosis.ca. Accessed July 6, 2020.

Papaioannou, A. et al (2010) “2010 clinical practice guidelines for the diagnosis and management of osteoporosis in Canada: summary.” CMAJ, November 23, 2010 182 (17) 1864-1873. Accessed July 10, 2020.

Radiological Society of North America (2018) “Bone Densitometry (DEXA, DXA).” www.radiologyinfo.org. Accessed July 6, 2020.

Saskatchewan Cancer Agency (2018) “Screening Program for Breast Cancer.” www.saskcancer.ca. Accessed July 10, 2020.