Invasive breast cancers

Invasive breast cancers make up most breast cancer diagnoses. There are more common and less common types. Different types of breast cancer have different treatments. 

A diagnosis of invasive breast cancer means cancer cells started in the breast tissue but:

• have spread outside the duct or lobule into other parts of the breast tissue
• may have spread to the lymph nodes in the breast or under the arm. 

Invasive ductal carcinoma

About 80% of all breast cancers are invasive ductal carcinomas.

This means the cancer begins in the milk ducts of the breast. Cancer cells then break through the lining of the milk duct and spread into the surrounding breast tissue.

Over time, invasive ductal carcinoma can spread to the lymph nodes and potentially to other parts of the body. 

Screening is important to identify invasive ductal carcinoma early. Self-examinations are also essential, so you notice any changes in your breasts. If you are diagnosed with invasive ductal carcinoma, find out about treatments.

There are also less common types of invasive ductal carcinoma. Their names often relate to how the cells look under a microscope. These include adenoid cystic, metaplastic, medullary, mucinous, cribriform, papillary and tubular carcinomas.

Invasive lobular carcinoma

Invasive lobular carcinoma is the second most common type of breast cancer. It begins in the milk-producing lobules of the breast. Cancer cells then break through the lining of the lobule and spread into surrounding breast tissue.

Over time, invasive lobular breast cancer can spread to the lymph nodes and potentially to other parts of the body.

Listen to the BCNA podcast episode on Invasive lobular carcinoma.

Rare types of invasive breast cancer

Paget’s disease of the nipple

Paget's disease of the nipple is a rare form of breast cancer. Cancer cells grow in the nipple or the area around the nipple (‘areola’). 

The first signs of this breast cancer are unusual changes in the nipple and areola. They often become scaly, red, itchy, and irritated.

Many people with Paget’s disease also have DCIS or invasive breast cancer somewhere else in the breast.

Read about Paget's disease at Rare Cancers Australia. 

Inflammatory breast cancer

Inflammatory breast cancer (IBC) is a rare and fast-growing form of breast cancer. It doesn't present like a typical breast cancer and often does not cause a breast lump. The cancer cells often block the lymph vessels and/or blood vessels of the breast. This causes the breast to become red, swollen and inflamed, and it may look like you have an infection.

If doctors suspect inflammatory breast cancer, they take a small skin sample (called a punch biopsy). This shows if there are any cancer cells in the skin, to confirm the diagnosis.

Cancer Australia has information about inflammatory breast cancer. The Inflammatory Breast Cancer Network Foundation also has information on this cancer and clinical trials. 

Phyllodes tumours of the breast

Phyllodes tumours of the breast are also rare. Most are not cancerous (they are ‘benign’) but some are cancerous (‘malignant’).

Phyllodes tumours tend to grow quickly, but they rarely spread outside the breast.

These tumours develop in the breast’s connective tissue or stroma (the tissue that holds everything together inside the breast). This is outside the ducts and lobules of the breast. 

The name phyllode (‘leaf’) comes from how the tumours look under a microscope. 

Stages and subtypes of invasive breast cancers

All breast cancers are tested to understand what subtype and grade they are. This information is important as it helps doctors make the best decisions about treatment.

Read about the Types, subtypes and stages. 

You can find this information in your pathology report.