Overview of Breast Cancer


If you're like me, pre-diagnosis, you probably thought breast cancer was "just" breast cancer! 

Actually it's far more complex than that and your treatment will depend on the "type" of breast cancer you have.  I've tried to summarise some of the more common types and terms below but there is no "one size fits all".

Please note this information is only meant to be a general overview and you can find much more information from your Breast Care Nurse.


Typically, after a suspicious area is found either at a mammogram or ultrasound, a biopsy of that area will be taken for further analysis.  That analysis will look at the cells and hormone receptors.  That will tell the Oncologist and team how best to treat the breast cancer.

Typically, you'll be told that your breast cancer is one of the following:

  • Estrogen-receptor-positive (or ER+).  This suggests that the cancer cells, like normal breast cells, may receive signals from estrogen that could promote their growth.  In these cases you want to lower the amount of estrogen in your body, thereby slowing down or halting the growth of the cancer cells.  Typically you will be given medication after your treatment (or during) to help with this.
  • Progesterone-receptor-positive (PR+) i- Like the above, if you are PR+ this means that the cancer cells may receive signals from progesterone that could promote their growth.

Two in every three breast cancers identified will be either ER+ or PR+.  With this type of breast cancer there is a "safety net" of drugs that can be taken after your treatment (either radiography or chemotherapys) has stopped to help prevent a recurrence.

  • HER2+ - this is a more complex type of cancer to try to describe and I've taken an extract from www.breastcancer.org as I feel that this gives a really thorough explanation.  ".... in about 25% of breast cancers, the HER2 gene doesn't work correctly and makes too many copies of itself (known as HER2 gene amplification). All these extra HER2 genes tell breast cells to make too many HER2 receptors . This makes breast cells grow and divide in an uncontrolled way. Breast cancers with HER2 gene amplification or HER2 protein overexpression are called HER2-positive in the pathology report. HER2-positive breast cancers tend to grow faster and are more likely to spread and come back compared to HER2-negative breast cancers. But there are medicines specifically for HER2-positive breast cancers"  
So, as with the other two categories above, there is a safety net for this type of cancer also and it's usually a combination of Herceptin injections and other medicines.

  • Triple Negative Breast Cancer (TNBC) - This type of breast cancer accounts for around 10-15% of those diagnosed.  Triple Negative means that there are no hormone receptors for estrogen, progesterone or HER2.  So they are ER-, PR- and HER2-.  Therefore, triple negative breast cancer does not respond to hormonal therapy.  However, it does respond very well to chemotherapy and there are many clinical trials to try to find a targetted therapy for when chemotherapy finishes.  For example, there are trials looking at PARP inhibitors and also another with Bisphosphonates.  If you are diagnosed with TNBC your first thought will be to panic but please bear in mind that once you reach 5 years clear, your chances of a recurrence are less, or equal to, the other more common types of breast cancer. 


An easy way to understand the Grade of cancer (not to be confused with "stage") is that it tells your medical team how fast or slow growing your cancer is and what the cells look like.  There are 3 Grades:

  • Grade 1 - These are the slowest growing cells and they're growing in a well organised format.  Not many of them will be making new cancer cells.
  • Grade 2 - These are growing faster than normal cells and do not look like normal cells.  They will also be dividing more quickly.
  • Grade 3 - These cells are messy looking without an organised pattern.  They are dividing very quickly to make new cancer cells.

Do not be alarmed if you are diagnosed with a Grade 3 cancer.  There is evidence that shows that chemotherapy and radiotherapy actually target the fast growing cells very effectively and these types of cells are vulnerable to those treatment plans.


At diagnosis you will be told where, in the breast, your cancer is.  Commonly these are the terms that are used:

  • Non-Invasive / Ductal Carcinoma In Situ (DCIS) - this is sometimes called an "early breast cancer" as the cancer is only found in the ducts or glands and hasn't spread outside those areas.  Some of these cancers, given time, may spread outside the areas and become "invasive".
  • Invasive - this is the most common type of breast cancer that's identified.  Up to 80% will have the label "invasive ductal carcinoma".  What this means is that the cancer has started in one of the ducts in the breast and then has spread outside the duct to the surrounding area.
    • Lobular (invasive or in situ) - this is a much rarer type of cancer and can be inside or outside the duct. This type of cancer is not common and only about 10% of cancers are lobular. Unlike the breast cancers mentioned above, with lobular cancer it normally doesn't present as a lump and can just be an area of fatty tissue.
    • Inflammatory Breast Cancer - this normally presents as a reddening of the skin and looks just like an inflammation. This is again quite rare.
    • Nodes - Although breast cancer doesn't start in the lymph nodes, breast cancer can spread to them. If you are having surgery to remove breast cancer, typically sentinel nodes will be removed at the same time (this is called a Sentinel Node Biopsy). Your surgeon will trace the path that your particular cancer would travel to to get to the nodes and then those nodes will be removed and sent to the lab for analysis to see whether cancer is detected in them. I believe there are upwards of 20 nodes on each side of the body but you may have 2, 5, 10 etc removed - it very much depends on your anatomy and where the breast cancer is found.


    You will often see the stages of breast cancer confused with grades.  Some are told what stage their breast cancer is and others are not.  Basically the stage refers to how large the tumour is, where it is, whether it has spread to the lymph nodes or to other areas of the body. 

    People (wrongly) assume that a diagnosis of Stage IV (the highest stage) is an automatic death sentence.  This is not the case and woman (and men) diagnosed with Stage IV breast cancer can live 10 years or more after diagnosis.  In these cases, the cancer may not be "curable" but it can be treatable and held at bay with the right treatment.  I won't detail the stages here but you can find more information online - a good place to start is either the Macmillan website https://www.macmillan.org.uk/ or breastcancercare.org.uk https://www.breastcancercare.org.uk/