Breast cancer may affect 1 in 9 Canadian women in their lifetime. It is the 2nd leading cause of cancer deaths in Canadian women, after lung cancer.
Though much less, men still do make up about 1% of all breast cancer cases. Their treatment is the same as that for women though early detection is less likely because it is not a likely pathology for men to be aware of.
Breasts are made up of glands, ducts and fatty tissue. Groups of glands are called lobules and these can produce milk. The milk then flows from the lobules through thin tubes called ducts towards the nipple. The fatty tissue lies between and around the ducts and the lobules.
THE LYMPHATIC SYSTEM
Breast tissue contains lymph nodes and lymph vessels that help make up the lymphatic system. The purpose of the lymphatic system is to help fight infection in the body. It does this by carrying lymph, a clear fluid containing immune system cells and waste products to the lymph nodes. Here, the lymph nodes trap harmful bacteria as well as cancer cells. Most lymph vessels of the breast lead to lymph nodes under the armpit, called axillary nodes.
WHAT IS BREAST CANCER?
Cancer in the breast is a malignant tumor that begins most commonly in the cells of either the ducts or the lobules. If it spreads to the lymph nodes, there may be noticeable swelling under the armpit in the axillary nodes. There are both non-invasive and invasive forms of breast cancer. Non-invasive refers to a cancer that has not spread beyond either the milk ducts or the lobules whereas invasive refers to a cancer that has spread further. There are several different types of breast cancer within these 2 categories, but I will mention just two of the most common.
DUCTAL CARCINOMA IN-SITU
This is the most common type of non-invasive breast cancer, is located within the milk ducts and has not spread any further. The lymph nodes have not been affected and treatment for women with this type of breast cancer is very successful.
INVASIVE DUCTAL CARCINOMA
This is the most common type of breast cancer. It begins within a duct, breaks through the wall of the duct and invades the rest of the breast tissue. It can continue to spread to other parts of the body from here. If a breast cancer does spread to the axillary lymph nodes, diagnosis, treatment options and quality of life may change. There is now a risk for developing lymphedema and this risk stays for the life of the woman.
Lymphedema can result from the removal of lymph nodes or radiation to this area. Once lymph nodes have been removed, there may be a build-up of lymph, as the system can no longer work as effectively. This can result in swelling of the chest area, arm or hand. Lymphedema may happen immediately post surgery or anytime thereafter. It can present in a mild form and be temporary or become a life-long, chronic and painful condition.
WHAT ARE SOME MODIFIABLE RISK FACTORS THAT CAN INCREASE OUR CHANCE OF HAVING BREAST CANCER?
Having a higher body weight
This is thought to do with the higher level of estrogen in the body, which has been linked to breast cancer. Especially after menopause, when the estrogen is mostly made in the fatty tissue, if a woman is carrying more weight, she will be exposed to more of this hormone.
Although not all people like to use the BMI, it is still widely used to ascertain whether or not someone is in a healthy weight range. If interested, below is the BMI formula and values.
Height in cm divided by Weight in kg
A healthy value is between 18.5 – 25 for less than 65 years of age
A healthy value is between 20 – 27 for 65 years and older
Being less active
Although not entirely clear, it is thought that women who are more physically active may have lower BMI’s, eat more nutritious foods and may be non-smokers. These lower the risk for getting breast cancer. Refer to the Canadian Society for Exercise Physiology for physical activity guidelines.
Alcohol is known as a cancer-causing substance. Approximately 4% of breast cancers in Canada may be linked to excessive alcohol consumption. Having just 1 drink per day may increase a woman’s relative risk of getting breast cancer by up to 13%.
Tobacco is a known carcinogen and we all know now that smoking or having exposure to second hand smoke can be deadly.
Exposure to hormones: the pill, HRT, IVF
Taking an oral contraceptive pill that contains both progesterone and estrogen will increase your risk for breast cancer slightly. There is some concern about using in-vitro fertilization (IVF) due to the fertility drugs causing a higher level of estrogen to be produced. Because hormone replacement therapy (HRT) also changes the levels of progesterone and estrogen in your body, there is a direct link to an increase in the risk of breast cancer while using it.
Pregnancy and Breastfeeding
Having your first child before the age of 30 appears to change the breast tissue such that it protects you against breast cancer. Women who are either nulliparous or who have their first child after the age of 35 show a low increase in the risk of developing breast cancer. If breastfeeding is an option for you, it will also decrease your risk of developing breast cancer. Because women who are breastfeeding usually stop having menstrual periods and therefore have fewer over their lifetimes, there will be less estrogen produced which decreases their risk of developing breast cancer.
It is advisable for all healthy women to have a mammogram every 2 years. In addition to this, performing regular self-examinations of your breast tissue will help in early detection of any potential tumors forming. Speaking with your family doctor to make sure you are not in a higher risk group (having family members with breast cancer) will also ensure that you are having the necessary tests done at the appropriate time.
Please refer to the Canadian Breast Cancer Foundation for further information.
Cathy Watson, BSCPT