Types of primary breast cancer

There are different types of breast cancer and it is important that your doctors have an accurate diagnosis so that they can begin to plan the most appropriate treatment for you.

DCIS

This stands for ductal carcinoma in situ. Ductal carcinoma in situ (DCIS) is an early form of breast cancer, sometimes described as an intraductal or non-invasive cancer. This means that cancer cells have developed inside the milk ducts, but remain entirely in-situ (in their place of origin) because they have not yet developed the ability to spread outside of these ducts, either within the breast or elsewhere in the body.

There are different grades of DCIS. If DCIS is left untreated, the cells may eventually develop the ability to spread from the ducts into the surrounding breast tissue and become an invasive cancer.

Invasive breast cancer

Invasive primary breast cancer is breast cancer that has the potential to spread from the breast to other parts of the body. Types of invasive breast cancer are outlined below.

Invasive ductal breast cancer

The vast majority of people with breast cancer have invasive ductal breast cancer, also known as 'no special type'. This means that the cancer cells have started within the milk ducts of the breast and have developed the ability to spread beyond the ducts and into the surrounding breast tissue.

Invasive lobular breast cancer

Invasive lobular cancer is less common, affecting about 10-15 per cent of all women with breast cancer. Men can get lobular breast cancer but it is very rare. It occurs when cancer cells in the lobules at the end of the breast duct have begun to spread outside the lobules and into the breast tissue around them.

Medullary breast cancer

Medullary breast cancer is a rare type of breast cancer that accounts for about five per cent of all breast cancers. It is an invasive cancer which means it has the ability to spread into surrounding tissue and to other parts of the body.

Metaplastic breast cancer

Metaplastic breast cancer accounts for less than five per cent of invasive breast cancers. The cells have undergone a transformation from one cell type into another (for example, from a glandular or epithelial type cell into a spindle or squamous cell type), which is the defining feature of this particular cancer. Metaplastic breast cancer is treated in the same way as other types of invasive breast cancer although is more likely to be triple negative.

Tubular breast cancer

Tubular breast cancer accounts for 1-2 per cent of all breast cancers. It is called tubular breast cancer because the cells under the microscope look elongated and tube-like. Tubular breast cancer is an invasive type of cancer.

Mucinous breast cancer

Mucinous (also known as colloid) breast cancer is known by this name because when it is looked at, under a microscope, the cells look like they are sitting in mucous. Mucinous breast cancer accounts for fewer than two per cent of all breast cancers. It is common to see mucinous cancer mixed with other types of breast cancer, such as invasive ductal breast cancer (often referred to as ‘no special type’).

Paget’s disease of the breast

Paget’s disease is a rare condition which is often noticed by changes to the nipple such as a red, scaly rash which can feel itchy or painful. The nipple may also become inverted.

Approximately half of all people with Paget’s disease will have an underlying breast lump, which is likely to be an invasive breast cancer. Where there is no lump, most will be non-invasive or in-situ cancers.

Inflammatory breast cancer

Inflammatory breast cancer is so called because the skin of the breast develops a red appearance and may feel warm and tender to the touch. The skin may also appear pitted like the skin of an orange. The reddened appearance is caused by cancer cells blocking tiny channels called lymph channels in the breast tissue.

Inflammatory breast cancer is rare and it is important to remember that the symptoms described above are also common symptoms of breast infections.

Malignant phyllodes tumour

Malignant phyllodes tumours are a rare type of breast cancer and account for less than one per cent of all breast cancers. A phyllodes tumour is a hard lump of tissue that can appear anywhere in the breast. Once formed a phyllodes tumour may grow quite large, quite quickly. Although they can affect a woman at any time in her life, phyllodes tumours are most common in women between 40 and 50 who haven’t yet been through the menopause. Phyllodes tumours can be classed into three types: benign (non-cancerous), borderline malignant and malignant. They are put into these three categories, according to what they look like under a microscope.

Triple negative breast cancer

This subtype of breast cancer is generally diagnosed based upon the lack of three "receptors". This means the breast cancer is oestrogen receptor negative, progesterone receptor negative and HER2 negative, thus giving rise to the name ‘triple negative’ breast cancer.