Not all breast cancers are the same and determining what kind of breast cancer you have will help your medical team to decide what is the most suitable and effective treatment for you. Most treatment for breast cancer involves surgery. During surgery breast tissue is removed and will then be examined by a pathologist who will provide information on the kind of breast cancer you have. 

Below you'll find information on:

Pathology report

Your pathology report will include information on the following:

  • your clinical history

  • a description of the tissue type removed e.g. breast or lymph node

  • clinical diagnosis – the initial diagnosis made before your tissue sample was tested

  • gross description – explains the size, shape and appearance of this tissue

  • microscopic description - explains how the cancer cells look under the microscope

  • information on blood and other tests for proteins, genetic components and details about how fast the cells are growing

  • final diagnosis.

You can read more about understanding your pathology report here.

Stages and grades

The aim of the pathology report and other tests such as chest x-rays, MRIs, or CT scans is to “set the stage” of your cancer. Setting the stage allows medical staff to determine how advanced or otherwise the cancer is. To determine the stage, the following are taken into account:

  • tumour size

  • whether lymph nodes are involved 

  • whether the cancer has spread beyond the breast and the underarm lymph nodes.

There are several different types of early breast cancer and these are outlined in the table below.

The stages of early breast cancer

Stage 0 Cancer has not spread beyond the ducts of the breast (also known as ductal carcinoma in situ or DCIS).
   
Stage I Cancer cells are found outside the ducts in normal breast tissue, with tumour size of 20 mm or less and no spread beyond the breast. This is often also called invasive breast cancer.
   
Stage II Invasive cancer in which the tumour size is: 20mm or less and has spread into a maximum of three underarm lymph nodes on the same side; over 20mm, but smaller than 50 mm with or without spread to maximum three  underarm lymph nodes on the same side; or 20-50mm and/or the cancer has spread to the underarm lymph nodes.
   
Stage III Tumour size is: greater than 50mm and has spread to one to three lymph nodes under the arm; smaller than 50 mm but has spread to four or more lymph nodes under the arm; or any size but with direct extension to the skin of the breast or to underarm lymph nodes the chest wall.

 

 The stages of advanced (metastatic) breast cancer

Breast cancer is considered advanced or metastatic if it has spread beyond the breast or armpit. 

Stage IIIB Tumour (any size) has spread to skin of breast, chest wall, internal mammary lymph nodes.
   
Stage IV Tumour has spread beyond breast, underarm, internal mammary nodes to other parts of the body – lungs, liver, bone, brain.

 

In addition to staging, the cancer will also be given a grade between one and three. The grade indicates how fast your cancer has been growing. Grade 1 is a slow growing cancer, grade 3 is a fast growing cancer and grade 2 is growing at a rate in between grade 1 and 3.

Staging and the cancer grade will help determine the best treatment for you. This is likely to include surgery and may also include chemotherapy, radiation therapy, endocrine therapy and targeted therapy.

Receptor status

Your pathology report will include information on the receptor status of your tumour. Breast cancer cells have surface 'receptors' for hormones (oestrogen and progesterone) and for the HER2 protein. Tests are carried out on the tumour sample to find out which receptors are abundant and which are not. 

This provides very valuable information for deciding on the best treatment for your breast cancer. For example, breast cancers with high levels of hormone receptors ('hormone receptor positive') will grow in response to the female hormones oestrogen and/or progesterone and can be treated with medicines that work to reduce hormone levels and control the cancer. Breast cancers with high levels of HER2 ('HER2 positive') can be treated with medicines that target and shut down the HER2 protein that drives the growth of this type of cancer.

Ki-67 and PD-L1 tests

Your pathology report may also give a Ki-67 score for your tumour. This measures the rate of cell proliferation. A high Ki-67 score indicates that cells are dividing rapidly and the cancer may grow quickly. Knowing the Ki-67 score can help with decisions about the types of surgery, radiation and medicines that might be needed in your treatment plan.

If you have been diagnosed with triple negative breast cancer (see table below), your pathology test might also include a PD-L1 score to determine how likely you are to benefit from treatment with an immune checkpoint inhibitor, such as pembrolizumab (brand name Keytruda). 

Genetic tests

Between 5 and 10% of breast cancers follow a familial pattern. The underlying genetics are not yet completely understood, but mutations of some genes, such as BRCA1, BRCA2 and PALB2, are well known to increase breast cancer risk. You can read more about hereditary breast cancer here.

If you were under the age of 40 when diagnosed with breast cancer, or diagnosed with triple negative breast cancer under the age of 60, or you are a man diagnosed with breast cancer, you may wish to ask your GP or specialist for a referral to the Genetic Health Service New Zealand for genetic testing. You can read more about this service here, and about the criteria for testing here.

Knowing if you carry any of the well-known breast cancer mutations can not only help your family members to understand their breast cancer risks and to undertake appropriate surveillance, but it can also help with decisions about your own treatment. For example, if you have triple negative breast cancer and a BRCA mutation, you may benefit from treatment with a PARP inhibitor.

Common types of breast cancer

The table below lists the most common types of breast cancer.

Hormone receptor positive  breast cancer    Your breast cancer responds to the hormones oestrogen and progesterone. Endocrine (hormone) therapy to block these hormones and stop your cancer from spreading or coming back will likely be part of your treatment plan. Tamoxifen and aromatase inhibitors (both pills) are commonly prescribed, often for many years to treat this type of breast cancer. Sometimes treatment to suppress your ovaries will also be recommended. About 75% of New Zealand women diagnosed with breast cancer have this type.
     
HER2-positive breast cancer   Your breast cancer produces more of the HER2 protein which affects how quickly the cancer cells will grow. Medicines that specifically target HER2 such as trastuzumab (brand names Herzuma or Herceptin) are often effective in treating this type of cancer. About 16% of all New Zealand women diagnosed with breast cancer have this type. Pasifika women have higher-than-average rates of HER2 positive breast cancer (24%), as do younger women (26% of those diagnosed when under 44 years old). 
     
Triple negative breast cancer   Your breast cancer is not responsive to oestrogen, progesterone or HER2 proteins and will not respond to medicines that block them.  Your treatment plan will involve chemotherapies and perhaps also an immune checkpoint inhibitor such as pembrolizumab (brand name Keytruda). If you have a BRCA mutation, you might also benefit from treatment with a PARP inhibitor. About 10% of all New Zealand women diagnosed with breast cancer have triple negative breast cancer. Younger women have higher-than-average rates of this type (14%).
     

 

Other types of breast cancer

Lobular carcinoma in situ (LCIS)   Abnormal cells are found in the lobules of the breast, but are contained to this area. This is NOT invasive breast cancer and does not need to be treated if there are no other changes to the breast. A woman with LCIS is, however, at greater risk of developing breast cancer and should have regular check ups.
     
Inflammatory breast cancer   This is a rare invasive form of the disease. It does not form as a lump, but spreads along the blood vessels in the skin of the breasts causing them to become red, inflamed and dimpled. Treatment should be sought as soon as symptoms are identified.
     
Paget's disease of the nipple    An invasive form of cancer that affects the nipple and area around the nipple.  It can appear as a crusty rash or eczema around the nipple, or the nipple may be red, inflamed and itchy. Many women with this form of the disease will also have breast cancer somewhere else in the same breast.

 

Find out more:

  • Click here for more information about breast cancer treatments.

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