Who is at risk?

All women above 20 are at risk of developing breast cancer. There are a number of risk factors that have been identified.

Some of these factors include:

	Age - the risk of developing breast cancer does increase with age. In fact, 70% of breast cancers occur in women aged 50 and above.
	A family history of breast cancer - women who have a mother, sister or daughter who developed breast cancer before the age of 50 are at a higher risk. This risk is further heightened if a woman has more than one immediate family member who has breast cancer.
	Previous history of breast cancer - women who have already been treated for cancer in one breast have an increased risk of developing cancer in the other breast.
	Early menstruation (before age 12 ) or late menopause (after age 50).
	Never having a full-term pregnancy or giving birth after age 30.
	Not having breast-fed
	High fat diet
	Low fibre diet
	Being obese in post-menopausal years
	Excessive alcohol consumption source : MAKNA

Inside Breast Tissue

The main parts of the female breast are lobules (milk-producing glands), ducts(milk passages that connect the lobules and the nipple), and stroma (fatty tissue and ligaments surrounding the ducts and lobules, blood vessels, and lymphatic vessels). Lymphatic vessels are similar to veins but carry lymph instead of blood. Most breast cancer begins in the ducts (ductal), some in the lobules (lobular), and the rest in other breast tissues.

Lymph is a clear fluid that carries tissue waste products and immune system cells. Most lymphatic vessels of the breast lead to underarm (axillary) lymph nodes. Some lead to lymph nodes above the collarbone (called supraclavicular lymph nodes) and others to internal mammary nodes which are next to the breastbone (or sternum). Cancer cells may enter lymph vessels and spread along these vessels to reach lymph nodes. Cancer cells may also enter blood vessels and spread through the bloodstream to other parts of the body.

Lymph nodes are small, bean shaped collections of immune system cells important in fighting infections. When breast cancer cells reach the axillary lymph nodes, they can continue to grow, often causing swelling of the lymph nodes in the armpit or elsewhere.

If breast cancer cells have spread to the axillary lymph nodes, it makes it more likely that they have spread to other organs of the body as well

sources : NCCN