Medullary breast cancer (sometimes called classic medullary breast cancer) is a rare type of breast cancer.
A pathologist (doctor who examines tissue removed during a biopsy or surgery) looks at the cancer cells under a microscope to see what type of breast cancer it is.
Medullary breast cancer and atypical medullary breast cancer (when some but not all the features of medullary breast cancer are seen under a microscope) are sometimes referred to as medullary-like breast cancer. Invasive ductal breast cancer (often called ‘no special type’ or NST) can also have medullary-like features. Together these account for around 3-5% of all breast cancers.
Medullary breast cancer is an invasive type of cancer, which means it has the potential to spread from the breast to other parts of the body, although this is not common with this type of breast cancer.
Although each case is different, the outlook for medullary breast cancer is often better than for some other more common types of invasive breast cancer.
Who gets medullary breast cancer?
Medullary breast cancer can occur at any age but it is more often diagnosed in younger women. It is also more common in women who have inherited an altered BRCA1 gene. It can also occur in men but this is very rare.
Medullary breast cancer is diagnosed in the same way as other breast cancers. Tests may include a mammogram (breast x-ray) and/or an ultrasound scan, followed by a fine needle aspiration (FNA) and/or core biopsy.
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 type of surgery you’ll be offered depends on where in the breast the cancer is, how big the cancer is in relation to the size of your breast and whether it’s found in more than one area of the 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).
Medullary breast cancer is less likely to spread to the lymph nodes (glands) under the arm than other types of breast cancer. However, your specialist team will want to check your lymph nodes, as it helps them decide whether or not you will benefit from any additional treatment after surgery. To do this, your surgeon is likely to recommend an operation to remove either some (a sentinel lymph node biopsy or sample) or all of the lymph nodes (a lymph node clearance).
Sentinel lymph node biopsy is widely used for people with breast cancer whose tests before surgery show no evidence of the lymph nodes containing cancer cells. It identifies whether or not the first lymph node (or nodes) the breast drains into is clear of cancer cells. If it is, this usually means the other nodes are clear too, so no more nodes will need to be removed.
If the results of the sentinel lymph node biopsy show that the first node (or nodes) are affected, your surgical team may recommend further surgery or radiotherapy to the remaining lymph nodes.
If the tests carried out before your breast surgery show that your lymph nodes contain cancer cells, the surgeon will usually recommend a lymph node clearance at the same time as your operation.
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 can include:
- hormone therapy
- targeted therapy.
Sometimes chemotherapy or hormone therapy may be given before surgery. This is known as neo-adjuvant or primary 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.
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.
If have breast-conserving surgery you will usually be offered radiotherapy to the breast to reduce the risk of the cancer coming back in the same breast. Sometimes you may be offered radiotherapy to the nodes under your arm.
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.
Hormone (endocrine) therapy
Hormone therapy will only be prescribed if your breast cancer has receptors within the cell that bind to the hormone oestrogen (known as oestrogen receptor positive or ER+ breast cancer). All breast cancers are tested for oestrogen receptors using tissue from a biopsy or after surgery. When oestrogen binds to these receptors, it can stimulate the cancer to grow. If your cancer is oestrogen receptor positive, your specialist will discuss with you which hormone therapy they think is most appropriate
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.
The most widely-used targeted therapy is trastuzumab (Herceptin). Only people whose cancer has high levels of HER2 (called HER2 positive) will benefit from having trastuzumab. HER2 is a protein that makes cancer cells grow.
There are various tests to measure HER2 levels which are done on breast tissue removed during a biopsy or surgery.
Medullary breast cancer is usually HER2 negative. If your cancer is found to be HER2 negative, then trastuzumab will not be of any benefit.
Triple negative breast cancer
When breast cancers are HER2 negative, oestrogen receptor 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 some other types of triple negative breast cancer.