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Second primary diagnosis

If you’ve had breast cancer in one of your breasts, you’re at a slightly higher risk of developing a new primary breast cancer. This is called a second primary diagnosis. Read more about this below.

1. A new breast cancer

Anyone who's had breast cancer in one of their breasts has a slightly higher risk of developing a new primary breast cancer.

People who developed breast cancer because of inheriting an altered gene also have an increased risk of a new cancer.

A second primary diagnosis refers to a new cancer. It’s not the same as a , when the original breast cancer has returned.

A second primary breast cancer is also not the same as secondary breast cancer, when breast cancer cells have spread from the breast to other parts of the body.

2. Diagnosing a second primary breast cancer

When doctors carry out tests on the cancer, they can usually tell if it’s a new cancer or if the original cancer has come back.

A second primary breast cancer may happen in the same breast after breast-conserving surgery or, more commonly, in the other breast.

If a second primary breast cancer is found in your other breast, your doctor may suggest referral for a family history risk assessment.

A second primary diagnosis may be different from your first breast cancer. For example, your first breast cancer may have been oestrogen receptor positive (ER-positive) but your new primary breast cancer could be oestrogen receptor negative (ER-negative).

3. Treating a second primary breast cancer

Treatment for a new primary cancer will depend on the breast in which it is diagnosed.

The same breast as your first cancer

If it’s in the same breast as your first cancer, and you previously had a and , then a mastectomy is usually recommended.

This is because it’s not usually possible to give radiotherapy to the same area twice because of damage to the tissue.

The other breast

If the new primary cancer is diagnosed in the other breast then, as with your first breast cancer, the type of surgery recommended will depend on the size and location of the cancer.

Treatment for the new breast cancer will be decided based on your individual situation. This will depend on features such as:

4. Prognosis (outlook)

The prognosis (outlook) for a new primary breast cancer will depend on the individual features of the new cancer, such as the grade and stage.

Having a new diagnosis of primary breast cancer is not in itself thought to affect the overall prognosis.

5. How you might feel

Having a new primary breast cancer can come as a shock.

It might be hard to accept that you have to go through treatment all over again when you thought you had put that part of your life behind you.

For some people it may feel a little less frightening this time around. For others it may be more frightening.

It’s important that you have a chance to ask questions. Your specialist is often the best person to ask as they can give you information about your individual situation. Your breast care nurse can also be a source of information and support.

6. Further support

You can call our free helpline, below, to talk to one of our nurses or trained experts.

You may also find it helpful to talk it through with someone who’s been there. Our Someone Like Me service can put you in contact with someone who's been in a similar position to you - please see below.

And you can chat to other people who understand what you’re going through on our forum.

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Quality assurance

Last reviewed in May 2022. The next planned review begins in May 2024.

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