By Dr. Siân Iles
Medical Advisor, Nova Scotia Breast Screening Program
Screening mammograms are considered the international gold standard for detecting breast cancer early and can usually find lumps two or three years before a woman or her primary care provider can feel them. Finding cancer when it is small allows for more treatment options and a better chance of recovery. Research has shown a 25 per cent reduction in deaths from breast cancer among women who regularly screen.
I am very proud that Nova Scotia is the first province in Canada to provide standardized province-wide breast density measurement to all women who have a screening mammogram. This will ensure the same standard of care across Nova Scotia.
Breast density is the amount of breast tissue in the breast and is a risk factor for breast cancer. It can also hide cancer. On a mammogram breast tissue appears as white and often a cancer also appears as white. As a result it may be harder to see a breast cancer on a mammogram where there is a large amount of dense tissue.
Software called Densitas, based on early research performed right here in Nova Scotia, allows for a reliable and reproducible assessment of breast density. Radiologists can now spend their time looking for cancer rather than calculating breast density.
Being informed of her breast density empowers a woman as she now knows more about her body and her potential risk of breast cancer and how sensitive screening mammography may be in her case. However there are other important risk factors to be taken into consideration such as her age, family history, and oral hormone replacement treatment when determining risk. Breast density is just part of the picture.
It is important to realize that no screening mammogram is perfect no matter what the breast density and that women should be breast aware and take seriously any symptoms of breast disease such as a lump or thickening, change in shape of the breasts, drawing in of the nipple, changes in the skin around the nipple or nipple discharge even if they have recently had a normal screening mammogram. These should be discussed with her primary health care provider. If a woman is symptomatic she should have diagnostic breast imaging rather than screening mammography which requires a referral from a health care provider.
A woman can now include knowledge of her breast density in discussions with her primary care provider about her personal risk of breast cancer and the benefits and risks of choosing to be screened for breast cancer.
A mammogram is the only screening test proven to reduce breast cancer deaths. Many cancers are seen on mammograms even if you have dense breast tissue.
All women should try to decrease their risk of breast cancer, maintaining a healthy body weight, exercising regularly and minimizing alcohol intake.