Understanding breast cancer - the basics

What is breast cancer?

Before discussing breast cancer, it's important to be familiar with the anatomy of the breast. The normal breast consists of milk-producing glands that are connected to the surface of the skin at the nipple by narrow ducts. The glands and ducts are supported by connective tissue made up of fat and fibrous material. Blood vessels, nerves, and channels to the lymph nodes make up most of the rest of the breast tissue. The breast, all the things just mentioned, sit under the skin but on top of the chest muscles.

As in all forms of cancer, the abnormal tissue that makes up breast cancer is the patient's own cells that have multiplied uncontrollably. Those cells may also travel to locations in the body where they are not normally needed, which means the cancer is malignant.

Breast cancer develops in the breast tissue, primarily in the milk ducts (ductal carcinoma) or glands (lobular carcinoma). The cancer is still called and treated as breast cancer even if it is first discovered after travelling to other areas of the body such as the lungs, liver, or bones. In those cases, the cancer is referred to as metastatic or advanced breast cancer.   

Breast cancer usually begins with the formation of a small, confined tumour (lump) and then spreads through channels to the lymph nodes or through the blood stream to other organs. The tumour may also grow and invade tissue around the breast, such as the skin or chest wall. Different types of breast cancer grow and spread at different rates, some take years to spread beyond the breast while other move quickly.  

Some lumps are benign (not cancerous). The only safe way to distinguish between a benign lump and cancer is to have the tissue examined by a doctor.

Cancer Research UK says breast cancer is the most common cancer in the UK despite the fact that it is rare in men, with men accounting for less than 1% of all cases.
In 2008, there were over 48,000 new cases of breast cancer diagnosed in the UK.

Most women with breast cancer are over the age of 50. Fortunately, breast cancer is very treatable if detected early. Localised tumours can usually be treated successfully before the cancer spreads. Overall, in England and Wales, 82 out of every 100 people diagnosed with breast cancer live for at least 5 years after diagnosis.  About 73 out of every 100 people live for at least 10 years.  The figures for Scotland are very similar. Experts usually consider a five year survival to be a cure although late recurrences do occur.

Once the cancer begins to spread, getting rid of it completely is more difficult, although treatment can often control the disease for years. Around 90% of women diagnosed with stage one breast cancer survive beyond five years. This drops to around 10% diagnosed with stage four breast cancer.