A woman's breast is made up of milk glands and milk ducts, surrounded by fatty tissue and connective supports. Uncontrolled growth of cells in any of these breast tissues can cause breast cancer.
Breast cancer is the most common cancer among women. It tends to occur at an earlier age than do other cancers or heart attacks and strokes. Chances of developing breast cancer rise dramatically as women age: up to age 39, the chances of getting the disease are about 1 in 231; from age 40 to 59, the risk has gone up to 1 in 25, and from age 60 to 79, it's nearly 1 in 15.
Breast cancer is rare in men, accounting for less than 1% of all cases. Breast cancer is the second most common cause of death from cancer in women.
The body's cells reproduce themselves throughout your lifetime, as tissues wear out and their cells are replaced in a controlled manner. Breast cancer - like all cancers - occurs when that control is lost and cells begin to divide at an unusually high rate.
No single trigger or cause has been identified for breast cancer. Certain risk factors exist, though, that increase a woman's chance of developing it:
The increased risks of getting breast cancer associated with the above factors are often statistically quite small. In fact, for most women, the only risk factor they have is being over 50 years of age. Any concerns should be discussed with your doctor.
9 out of 10 times, women are the first to notice a lump or mass in their breast. It usually isn't painful, but can cause an unusual sensation in the area where the lump is.
When a tumour grows in the milk ducts, bleeding can occur from the nipple. The size or shape of the breast may change. As well, the nipple might draw in, or some of the skin will pull in, causing what looks like a dimple to appear. Other symptoms may include a lump or swelling in the armpit and redness or swelling of the breast.
While these might be signs of breast cancer, they might also indicate another non-cancerous condition. In fact, about 8 out of 10 breast growths are non-cancerous. However, a doctor should be consulted to determine the exact cause of the lump.
The most serious complication of breast cancer is metastasis. That's when some cells from a tumour break off and move to other areas of the body, either through the blood or the lymphatic vessels - invading the tissue at new, possibly distant sites. When breast cancer cells metastasize, it's most commonly to the lymph nodes, lungs, liver, bones, brain, and skin. It can take years, even after the breast tumour is diagnosed and treated, before cancer that has spread from the original tumour appears.
Once metastatic tumours are discovered, chances are that the cancer has spread to other locations as well, even if they remain undetected.