Invasive lobular breast cancer accounts for up to 15% of all breast cancers. It can occur at any age but is most common in women who have been through the menopause.
Men can also get invasive lobular breast cancer but this is very rare.
Breast cancer starts when cells in the breast begin to divide and grow in an abnormal way.
Invasive lobular breast cancer occurs when these abnormal cancer cells have started to grow within the lobules (milk-producing glands) and then spread into the surrounding breast tissue.
What are the symptoms?
Invasive lobular breast cancer may not cause any obvious changes to the breast.
You may notice a hardened or thickened area of breast tissue rather than a definite lump.
Other changes in the breast may also occur, such as dimpling or flattening of an area, or the nipple turning inward.
How is it diagnosed?
Invasive lobular breast cancer can be difficult to diagnose if there are no obvious symptoms. In some women it’s found during routine breast screening before any symptoms are noticed.
If you have been referred to a breast clinic, your breasts (including the area under your arms and up around the collar bone) will be examined by a doctor or specialist nurse.
You will then usually have a mammogram. However, some invasive lobular breast cancers can be difficult to see on a mammogram.
As well as a mammogram you’ll probably have an ultrasound scan of the breast and the axilla (under the arm), a core biopsy and possibly a fine needle aspiration (FNA).
Find out more about mammograms and other tests.
Invasive lobular breast cancer can sometimes be more difficult than other types of breast cancer to identify and measure using an ultrasound or mammogram, so you may have a magnetic resonance imaging (MRI) scan. An MRI uses magnetic fields and radio waves to produce a series of images of the inside of the breast and can sometimes provide a more accurate picture of the size of this type of cancer, and whether it affects more than one area in the breast. Both breasts will be checked.
Sometimes more than one area of invasive lobular cancer is found in the same breast.
Having breast cancer in one breast means the risk of developing cancer in the other breast is slightly higher than in someone who’s never had breast cancer. With invasive lobular breast cancer, this risk may be slightly higher than with other types of breast cancer, but it’s still very low overall.
What are the treatments?
Surgery is usually the first treatment for invasive lobular breast cancer. This may be breast-conserving surgery (the removal of the cancer and an area of normal breast tissue around the cancer) or a mastectomy (the removal of all the breast tissue and nipple area).
The type of surgery recommended will depend on the area of the breast affected, the size of the cancer compared to the size of your breast, and whether more than one area in the breast is affected.
If breast-conserving surgery is being considered, an MRI scan may be recommended to assess the size of the cancer (if you haven’t already had one to confirm the diagnosis). Your breast surgeon will discuss this with you.
Even after an MRI scan it can sometimes be difficult to estimate the size of an invasive lobular breast cancer before surgery. Because of this, some women who have breast-conserving surgery may need a second operation. This is to ensure all the cancer, and a margin (border) of normal breast tissue around it, has been removed. In some cases, a mastectomy will be recommended as the second operation.
If you have invasive lobular breast cancer in more than one area of the breast, the surgeon may recommend a mastectomy. However, this will depend on the position of the areas affected and the size of your breast.
If a mastectomy is recommended, or if you choose to have a mastectomy, you will usually be able to have breast reconstruction. This can be done at the same time as your mastectomy (immediate reconstruction) or sometime in the future (delayed reconstruction).
Surgery to the lymph nodes
Your doctors will also want to check whether breast cancer cells have spread from the breast to the lymph nodes (glands) under the arm. This will help them decide whether you will need additional treatment after surgery. To do this, 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).
A widely used method for checking these lymph nodes is called sentinel lymph node biopsy. Sentinel lymph node biopsy isn’t suitable for everyone, and your surgeon will discuss whether it’s an option for you.
If the results of the sentinel lymph node biopsy show that the first node (or nodes) are affected you may be recommended to have further surgery or radiotherapy to the remaining lymph nodes.
What are the adjuvant (additional) treatments?
After surgery you may need further treatment. This is called adjuvant (additional) therapy and includes chemotherapy, radiotherapy, hormone therapy and targeted therapies. Which treatment you have will depend on your individual situation.
The aim of these treatments is to reduce the risk of breast cancer cells returning in the same breast or developing in the other breast – or spreading somewhere else in the body.
Sometimes chemotherapy or hormone therapy may be given before surgery. This is known as neo-adjuvant or primary therapy.
Chemotherapy is recommended for some people. This will depend on various features of the cancer, such as its size, its grade (how quickly the cells are dividing and how different they are to normal breast cells) and whether the lymph nodes are affected.
If you have breast-conserving surgery, you will usually be given radiotherapy to reduce the risk of the breast cancer returning in the same breast. Sometimes you may be offered radiotherapy to the nodes under your arm.
If you have a mastectomy, you may be given radiotherapy to the chest in the area where you had your surgery. This may be the case if the tumour was large, if there’s a high risk that cancer cells may have been left behind or if cancer cells are found in the lymph nodes under the arm (axilla).
Hormone (endocrine) therapy
As the hormone oestrogen can play a part in stimulating some breast cancers to grow, there are a number of hormone therapies that work in different ways to block the effect of oestrogen on cancer cells.
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.
Targeted therapies block the growth and spread of cancer. They target and interfere with 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 (HER2 positive or HER2+), a protein that makes cancer cells grow, will benefit from having trastuzumab.