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Breast cancer pathology

Breast cancer pathology 

Updated: 11 Jul 2023
Close up of someone in a pathology lab pouring a liquid into test tubes

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During your breast cancer surgery, your surgeon will remove the tumour and a small amount of healthy tissue surrounding it. This will be sent to a pathology laboratory for testing.

The results of these tests will provide important information such as whether all the cancer has been removed, how big the tumour is, and how fast the cancer cells are growing.

This information helps your medical team to decide the best treatment options for you.

Below is a list of some of the key pieces of information usually included in a pathology report. 

The pathology report usually includes: 

  • Your diagnosis – for early breast cancer, the diagnosis will be described as ‘invasive breast cancer’. 

  • Location of your breast cancer – where it was located in the breast. 

  • Microscopic examination – what the pathologist found when looking at sections of the tissue under a microscope. It includes all the information needed by your treating team, such as: 
    Type – ductal or lobular are most common (but there are many different types) 
    Grade – system to classify cancer cells according to how different they are to normal breast cells and how fast the cells are growing. Usually numbered from 1 to 3, where a low grade (1) is slow growing cells, and a high grade (3) is faster growing cells. 
    Stage – usually numbered from 0-4 and indicates the size of the breast cancer and the body parts affected.  

  • Surgical margin – when a breast cancer tumour is removed, the surgeon will also remove some of the healthy-looking tissue around it to ensure that all the cancer has been removed. If there are no cancer cells in the healthy-looking tissue, the surgical margin is ‘clear’. If the margin is not clear, you may need more surgery to ensure that all of the cancer is removed. 

  • Lymph nodes – shows if any cancer cells were found in the lymph nodes removed from your breast or armpit (axilla), and if so, how many lymph nodes, what size and whether the cancer extended into the surrounding tissue. This is one of the factors that affects whether chemotherapy is recommended for you. 

  • Hormone receptors – whether hormone receptors are present on your breast cancer. This will affect whether hormone-blocking therapy is recommended for you. There are two types of hormone receptors – oestrogen (ER) and progesterone (PR). If your breast cancer is positive for these receptors it will be reported as ER+ and/or PR+. Hormone positive breast cancers are divided into two categories:

    • Luminal A – these tumours are oestrogen receptor positive (ER+) and are often low grade with slow tumour growth. 

    • Luminal B – these tumours are also ER+ but with quicker tumour growth than Luminal A. 

  • HER2 status – this shows if there are too many HER2 receptors on your breast cancer cells. HER2 is a protein on a cell that affects the growth of the breast cancer. If your cancer is HER2 positive, treatment such as trastuzumab may be recommended for you. 

  • Ki-67 – this is a protein in cells that increases when cells are dividing. Sometimes the pathology report shows the percentage of cells containing Ki-67. The more positive cells there are, the more quickly they are dividing and forming new cells. Luminal B tumours have higher Ki-67 than Luminal A. 

  • Summary – this is a summary of the information in the report and will also include your diagnosis. 

If there is anything you do not understand about your pathology report, talk to a member of your treating team. 

Things you can do now

  • Read BCNAs pathology factsheet for more information

  • Visit My Journey, BCNA’s online tool for information tailored to your diagnosis. My Journey has a Symptom Tracking tool that you can use to help you record your pain, what works for you and what doesn’t.  

  • Join our Online Network if you think that talking to others online and sharing experiences will help.  

  • Contact BCNA’s Helpline on 1800 500 258 between 9.00 am to 5.00 pm AEST Monday to Friday, for information about the services and support that may be available for you and your family. 

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