What is Breast Cancer?

Cancer cells are different from normal cells, as they go on to grow and multiply when they should not; to form lumps and/or tumours.

Different Types of Breast Cancer

There are different types of breast cancer, which are classed as invasive and non-invasive depending on their ability to spread to neighbouring tissues.

Non-invasive

DCIS

The most common type of non-invasive breast cancer is Ductal Carcinoma In Situ (DCIS).

Cancer cells are found inside the milk ducts but have not yet spread through the walls of the ducts into the breast tissue. The importance of DCIS is that it may over time develop into the invasive form of breast cancer; this process is, however, very unpredictable and may take many years. Since there is often no lump, non-invasive breast cancer is commonly detected by breast screening. Nearly everyone diagnosed with DCIS is able to have the cancer in the affected breast completely removed.

LCIS

Another form of non-invasive breast cancer is Lobular Carcinoma In Situ (LCIS).

It is most often found by chance, in a sample of breast tissue removed for some other reason. LCIS is a diffuse process, the main relevance of which is that it identifies a woman who is at increased risk of the development of breast cancer in the future. LCIS is managed by regular mammogram check-ups to look out for the earliest signs of a problem.

Invasive

IDC

Invasive breast cancer usually comes to notice because it produces a lump in the breast. The most common type of invasive breast cancer is called Invasive Ductal Carcinoma (IDC) which is responsible for around 80% of all breast cancers. These cancer cells are found in the ducts and in the breast tissue. These cells also have the ability to spread to other parts of the body.

ILC

Invasive Lobular Carcinoma (ILC) accounts for between 10-15% of all breast cancers. With ILC, cancer cells initially grow in the lobes of the breast and have the ability to spread to other areas of the breast and to other parts of the body.

Secondary Breast Cancer

Secondary breast cancer occurs when breast cancer cells spread from the primary (first) cancer in the breast to other parts of the body. Breast cancer cells can spread to another part of the body through the lymphatic system or the blood stream.

You may also hear secondary breast cancer referred to as:

metastatic breast cancer
metastases
advanced breast cancer
secondary tumours
secondaries
stage 4 breast cancer

Usually, secondary breast cancer occurs months or years after primary breast cancer. But sometimes it's diagnosed at the same time as the primary breast cancer or before the primary breast cancer has been diagnosed.

The most common areas breast cancer spreads to are the:

bones
lungs
liver
brain

When breast cancer spreads to the bones, for example, it’s called secondary or metastatic breast cancer in the bone. The cancer cells in the bone are breast cancer cells.

Risk Factors

There are certain factors which have been found to increase the risk of developing breast cancer:

Age: Approximately 80% of women diagnosed with breast cancer are over the age of 50.
Family History: Women whose mother, sister or daughter have developed breast cancer, have double the risk of developing breast cancer themselves.
Cancer in one breast: If a women has had cancer in one breast already, there is an increased risk of developing a new cancer in the other breast.
Age when periods start: If periods started early (before age 12) of if menopause happened after the age of 50.
Exposure to radiation: such as radiotherapy at a young age e.g. for treatment of Hodgkins disease.
Taking hormones: Women who take the pill or are on HRT have a slightly increased risk of breast cancer (while the risk of other cancers is reduced).
Obesity: There is some evidence to suggest that being very overweight can contribute to the risk.
Diet: Diets that are high in fat and alcohol are linked to an increased risk of breast cancer.
Not breast-feeding: There is evidence that women who breast feed are at less risk of developing breast cancer.

What is Breast Cancer?

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