Information about your breasts

In order to understand how breast cancer can develop, it is important to know what the female breast is made of.

The mature female breast is made up of four essential structures: lobules (glands); (milk)ducts; fat; and connective tissue.

The upper, superficial, area of the breast is mostly made up of glandular tissue. This tissue is what is responsible for the tenderness that many women experience before their menstrual cycle. This is also where almost 50 percent of the breast cancer cases are located.

The lobules, as you can see in the picture, group together, forming larger units called lobes. The average breast has between 15 and 20 lobes, which form a spoke pattern originating from the nipple/areola area.

The lobes run into the (milk)ducts which continue through the breast towards the nipple. Once arrived at the nipple, the ducts merge into 6 to 10 larger ducts, called collecting ducts, which connect to the outside.

Lymph nodes run through the entire body, and act as filters for foreign particles, such as cancer cells. The lymph nodes found around the armpit are the most important when it comes to diagnosing breast cancer. Because breast cancer often first spreads to the lymph nodes in the armpit, from the breasts, doctors can determine which stage the breast cancer is in, and in turn, determine the treatment.

The breasts of younger women are mainly made up of glandular tissue, with on average only a small percentage being fat (depending on the woman general percentage of body fat). Therefore the breasts are firmer than in older counterparts. As women grow older, especially due to the loss of estrogen at menopause, the lobes shrivel and are replaced by fat. The breasts become softer, and lose their support. Physical examination and mammography are easier to interpret and are also more accurate.

All components of the breast are influenced by hormones, the glandular tissue being the most sensitive. Very dramatic and totally normal changes can occur in the consistency of the breasts during the menstrual cycle. These changes are most pronounced just before the menstruation, when levels of estrogen and progesterone are at their highest. Right after menstruation, hormone levels are at their lowest and the breast becomes softer and less tender. This is also the best time to perform a self-breast exam or mammogram.

In post menopausal women, who are not taking estrogen supplementation, weight becomes a significant factor in the size and appearance of the breasts. Being mostly composed of fat at this point, small changes in body weight can produce significant changes in breast size.


Understanding cancer

Cancer is a class of diseases in which a group of cells display the traits of uncontrolled growth, invasion, and sometimes metastasis. These three malignant properties differentiate cancer from benign tumors, which are self-limited, do not invade or metastasize. Most forms of cancers form a tumour but some, like leukemia, do not.

Cancer originates in cells, the building blocks that make up tissues, which in turn make up human organs. Normally, cells only generate new cells when the body needs them. When cells grow old, they die, and the new cells take their place. Sometimes, this process goes wrong, and new cells form when the body does not need them, or old cells do not die when they should. This is what is referred to as uncontrolled growth.

The second malignant property, invasion, is when a tumor has formed, due to uncontrolled growth, and cells break away from the tumor and crawl through surrounding tissues. This property enables the cancer cells to move into a blood vessel and be transported through the body, possibly establishing a secondary tumor. The creation of this second tumor is also the third malignant property of cancer cells, the metastasis.

Once breast cancer cells spread, the cancer cells are often found in lymph nodes near the breast. But, breast cancer can spread to almost any other part of the body. The most common places where breast cancer spreads to are the bones, liver, lungs, and brain. The new tumors that are a result of the metastasis, have the same kind of abnormal cells and the same name as the original tumor in the breast. For example, if breast cancer spreads to the lung, the cancer cells in the lung are actually breast cancer cells. The disease is metastatic breast cancer, not lung cancer. For that reason, it is treated as breast cancer, not lung cancer. Doctors call the new tumor “distant” or metastatic disease.

Cancer risk

All women are at risk when it comes to breast cancer, but no one knows what exactly causes breast cancer. Doctors often cannot explain why one woman develops breast cancer and another does not. Research has shown that women with certain risk factors are more likely than others to develop breast cancer.

Some examples of risk factors are:

  • Cancer is heredatary; If your sister, mother, or daughter developed breast cancer, then you have a higher risk of developing it yourself.
  • Your own personal history with cancer;
  • The age at which your menstrual cycle began; how earlier your cycle began, how higher the risk.
  • The age at which you go through menopause; women who have their menopause after the age of 55 are at higher risk of developing breast cancer.
  • The age at which you give birth to your first child; the risk increases with older age, but if you have first degree relatives with carcinoma of the breast, then risk goes down.
  • Your current age; The risk increases with age. Age is the biggest risk factor. (76% of women who develop breast cancer had no other risk factors).
  • Your race; Caucasian women have a slightly higher risk than Black, Hispanic, or Asian women.
  • Your health; women who are overweight or obese after their menopause have a higher risk of developing breast cancer.
  • Drinking alcohol; studies suggest that the more alcohol a woman drinks, the greater her risk of breast cancer.

Many risk factors can be avoided, others, such as family history, cannot. Women can help protect themselves by staying away from known risk factors whenever possible, but shouldn’t let it dominate their life. It is important to keep in mind that most women who have known risk factors do not get breast cancer, and most women with breast cancer do not have a family history of the disease. In fact, except for growing older, most women with breast cancer have no clear risk factors. If you think you may be at risk, you should discuss this concern with your physician. He or she may be able to suggest ways to reduce your risk, and can plan a schedule for checkups.

Recent publications suggest that certain diets decrease the risk of cancer in general. For more information on “anticancer foods” check out this section of our website.

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