Types of breast cancer

Breast cancer occurs when the cells in your breast tissue grow in an abnormal way. It can affect how your breasts work normally. There are many different kinds of breast cancer.
Breast cancer is currently the second most common cancer in women in Ireland. Each year it affects about 3,000 women and 20 men in this country.

The video above tells you all about breast cancer. The information in this video was correct as of  08 June 2015.

Invasive ductal breast cancer

This is the most common type of breast cancer (also known as Infiltrating or Infiltrating ductal carcinoma). It starts developing in the milk ducts of your breast, but breaks out of the duct tubes, and invades, or infiltrates the surrounding tissue of the breast. Over time, invasive ductal carcinoma can spread to the lymph nodes and possibly to other areas of the body. Invasive ductal carcinoma accounts for about 8 out of 10 of all invasive breast cancers. Although this can affect women at any age, it is more common as women grow older.

For more information please read our booklet on Understanding Breast Cancer (pdf 2.63 MB).


DCIS is an early form of breast cancer. You may hear it described as a pre-cancerous, intraductal or non-invasive cancer, which means the cancer cells are inside the milk ducts or ‘in situ’ and have not developed the ability to spread either within or outside the breast.

For more information please see our factsheet on Ductal carcinoma in situ (DCIS) (pdf 317 KB).

Invasive lobular breast cancer

Invasive lobular breast cancer starts in cells that make up the lobules at the end of the ducts. Breast tissue is made up of ducts and lobules where milk is made, stored and carried through to the nipple during breastfeeding. 

Invasive lobular breast cancer is uncommon, and affects about 10-15% of all women with breast cancer. It can occur at any age, but more commonly affects women in the 45-55 year age group.

Men can also get invasive lobular breast cancer but this is very rare. It is generally no more serious than other types of breast cancer. However, it is sometimes found in both breasts at the same time and there is also a slightly greater risk of it occurring in the opposite breast at a later date.

For more information see our page on invasive lobular breast cancer.

Inflammatory breast cancer

Inflammatory breast cancer is so called because the overlying skin of the breast has a reddened appearance – similar to that seen with some infections of the breast.

In patients with inflammatory breast cancer, the reddened appearance is caused by breast cancer cells blocking tiny channels in the breast tissue called lymph channels.

The lymph channels are part of the lymphatic system involved in the body’s defence against infections. Inflammatory breast cancer is a rare type of breast cancer, accounting for only 1-2% of all breast cancers.

For more information see our page on inflammatory breast cancer.

Paget's disease of the breast

Paget's disease of the breast is an uncommon form of breast cancer. This type of breast cancer starts in the breast ducts and spreads to the skin of the nipple and the areola the dark circle around the nipple. It occurs in around 1% of all women with breast cancer. Men can also get Paget´ disease but this is very rare.

For more information see our our page on Paget's disease of the breast.

Male breast cancer

This section discusses the main aspects of male breast cancer including what we know about why it happens, how it is diagnosed, the treatments and some ways of coping with the disease.

We hope it helps you to discuss any questions you might have with your specialist team and enables you to take part in your treatment plan.

We recommend that you read this with Action Breast Cancer’s booklet Understanding cancer of the breast booklet (pdf 2.63 MB). Although the booklet is aimed at women, much of the information is relevant to men.

Breast cancer in men is uncommon, with approximately 16 men diagnosed each year in Ireland.

For more information please see our page on male breast cancer.

Hereditary breast cancer

Hereditary breast cancer is cancer that runs in a family. Hereditary breast cancer can develop when a faulty gene is passed on from either parent. Most breast cancer is not hereditary.

For more information please see our page on hereditary breast cancer.

Younger women and breast cancer

Breast cancer in younger women (premenopausal) is not common. In fact, most cases occur in women over the age of 50. Many younger women think that breast cancer is a disease of older women and not something they have to worry about until later in life. As a result, you may feel shocked and isolated when faced with a breast cancer diagnosis. But remember you are not alone.

Our booklet Younger Women and Breast Cancer looks at issues you may have as a younger woman diagnosed with breast cancer.  However, we do advise you to read our booklet Understanding Cancer of the Breast, which can help you learn more about the treatment of breast cancer. 

Secondary breast cancer

Secondary breast cancer is cancer which started growing in the breast and has moved or spread to another parts of the body. You may hear the word metastases or metastatic breast cancer, this is just another name for secondary breast cancer.

Our booklet Understanding Secondary Breast Cancer looks at issues you may have when you are diagnosed with secondary disease. 

How common is breast cancer?

Breast cancer is rare in women under the age of 30 and occurs more often in women over the age of 50. Men also develop breast cancer but this is very rare: about 15 men develop breast cancer each year in Ireland.

Call our Cancer Nurseline

Freephone 1800 200 700 to talk to a specialist cancer nurse
It's open Monday-Thursday from 9am to 6pm and Friday from 9am to 5pm

Did you find the information on this page useful?

Date Last Reviewed: 
Monday, June 8, 2015
Date Last Revised: 
Monday, November 9, 2015