Medullary breast cancer is a rare type of breast cancer, accounting for around 3-5% per cent of all breast cancers.
Medullary breast cancer usually has a clear well defined border between the cancer and the surrounding breast tissue – a feature which pathologists use to help distinguish it from other types of breast cancer.
It’s an invasive cancer which means it has the potential to spread to surrounding breast tissue and to other parts of the body, although this is not common.
Although each case is different, the outlook for medullary breast cancer is often better than some other more common types of invasive breast cancer.
Who gets medullary breast cancer?
Medullary breast cancer is more common in women who inherit a faulty copy of the BRCA 1 gene. It can also occur in men but this is very rare.
Medullary breast cancer is diagnosed using a range of tests including a mammogram (breast x-ray) and an ultrasound scan, followed by a core biopsy or fine needle aspiration (FNA).
Find out more about diagnosing breast cancer.
As with all types of breast cancer, the features of your medullary breast cancer will affect what treatments you might be offered.
Breast surgery is usually the first treatment for medullary breast cancer.
This may be:
- breast-conserving surgery, usually referred to as wide local excision or lumpectomy. It is the removal of the cancer with a margin (border) of normal breast tissue around it
- mastectomy, which is the removal of all the breast tissue including the nipple area.
The amount of tissue removed depends on the area of the breast affected and the size of the cancer in your breast. Your breast surgeon will discuss this with you.
If you’re going to have a mastectomy, you’ll usually be able to have breast reconstruction either at the same time as your mastectomy (immediate reconstruction) or at a later date (delayed reconstruction).
Spread of breast cancer cells to the lymph nodes (glands) under the arm (axilla) is less common with medullary breast cancer than with other many other types of breast cancer. However your specialist team will want to check whether any contain cancer cells. This helps them decide whether you will benefit from additional treatment after surgery.
Your surgeon is likely to recommend an operation to remove either some (a lymph node sample or biopsy) or all of the lymph nodes (a lymph node clearance).
Sentinel lymph node biopsy is widely used for people whose tests before surgery show no evidence of the lymph nodes containing cancer cells. It identifies whether the first lymph node (or nodes) is clear of cancer cells. If it is, the other nodes are usually clear too, so no more will need to be removed.
If the first node or nodes are affected, further surgery to remove some or all of the remaining lymph nodes may be recommended. Sentinel lymph node biopsy is not suitable if tests before your operation show that your lymph nodes contain cancer cells. In this case it is likely that your surgeon will recommend a lymph node clearance.
Find out more information about breast surgery, including lymph node removal and sentinel lymph node biopsy.
Adjuvant (additional) treatment
After surgery, you may need further treatment. This is called adjuvant (additional) therapy and includes chemotherapy, radiotherapy, hormone therapy and targeted therapy.
The aim of these treatments is to reduce the risk of breast cancer returning in the same breast or developing in the opposite breast or spreading somewhere else in the body.
If you have breast-conserving surgery, it is likely your specialist team will recommend that your treatment includes radiotherapy.
In some circumstances, you may be recommended to have radiotherapy to the chest wall after a mastectomy, for example if some lymph nodes under the arm are affected.
For some people chemotherapy may be recommended. Sometimes chemotherapy is given before surgery to try to shrink the cancer. This is called neo adjuvant or primary chemotherapy.
Whether or not you’re offered chemotherapy depends on various features of the cancer, including its size, its grade and whether the lymph nodes are affected.
Hormone therapy will only be prescribed if your breast cancer has receptors within the cells that bind to the hormone oestrogen and stimulate the cancer to grow. This is known as oestrogen receptor positive (ER+) breast cancer.
All breast cancers are tested for oestrogen receptors using tissue from a biopsy or after surgery. However medullary breast cancer is more likely to be oestrogen receptor negative (ER –). If this is the case, then hormone therapy will not be of any benefit to you.
Find out more about when hormone therapy is given.
This is a group of drugs that block the growth and spread of cancer by interfering with the biology of the cancer cells. They target specific processes in the cells that cause cancer to grow.
Targeted therapies may be more effective and less harmful to normal cells than other cancer treatments. The most well known targeted therapy is trastuzumab (Herceptin). Only people whose cancer has high levels of HER2 (HER2 positive), a protein that makes cancer cells grow, will benefit from having trastuzumab.
Medullary breast cancer tends to be HER2 negative, meaning that trastuzumab will not be of any benefit.
When breast cancers are HER2 negative, oestrogen negative and also test negative for progesterone receptors, this is referred to as ‘triple negative’ breast cancer. This is quite common in medullary breast cancer.
If you have triple negative breast cancer, you may feel concerned that you are not able to have treatments such as trastuzumab or hormone therapy. However, people diagnosed with medullary breast cancer generally have a better prognosis (outlook) than people with other types of breast cancer.