Second Primary Cancers: Are They Recurring Cancers?


Most of us who have been diagnosed with breast cancer live with the fear of a recurrence. As the years take us away from our original experience, our confidence grows that breast cancer is a thing of the past. Few of us know much of anything about the possibility of a second primary breast cancer in our opposite breast. When many of us think of it, we tend to think and describe our fear of this event as our original breast cancer spreading to or coming back in our other breast.


In reality, a breast cancer that occurs in your opposite breast is usually not a recurrence of your original breast cancer. Rather, this occurrence is called a contralateral breast cancer and is described as a second primary breast cancer. It is not treated as a recurrence, but as a primary breast cancer. While most contralateral lesions are a second primary tumor, a metastasis can occur in the opposite breast, but this is most often associated with distant metastases.

Risk of Developing Second Primary Cancers

We may find ourselves asking our surgeons or oncologists about our risk for a cancer developing in our opposite breast. There is no easy answer to this question since many factors must be considered. When Dr. Jay K. Harness, medical director for, is asked about a patient’s odds for getting a breast cancer in the opposite breast, he shares that it is usually about 15% to 18% over the rest of a patient’s life.

He is quick to caution that there are other factors, such as a strong family history of breast cancer, with or without the BRCA mutations that can and will significantly raise the odds of getting a breast cancer in the opposite breast over the course of a patient’s lifetime.

Women who carry the BRCA1/2 mutations are at higher risk of a contralateral breast cancer if they choose breast conservation surgery (lumpectomy) to treat their first cancer than women who do not have the BRCA mutations.

 Women with the BRCA mutations that are diagnosed with their first primary breast cancer at a young age also have a higher 10-year risk of getting a cancer in the opposite breast.

A family history of having breast cancer is associated with an increased risk of contralateral breast cancer, with the highest risk being in BRCA1/2 mutation carriers.

Contralateral breast cancers are not just limited to families that carry the BRCA mutations though. There are many families that have a history of breast cancer and test negative for the BRCA mutations. In my family, 5 of 8 female cousins were diagnosed with breast cancer but tested negative for the BRCA mutations and any other known form of breast cancer. I am the only one, to date, that was diagnosed with a second primary cancer in my contralateral breast.

Learning Your Family History

We all need to know our family history of breast cancer. This is the only way we will be able to make an informed decision about getting genetic testing to determine if we are a BRCA carrier or have another hereditary form of breast cancer.

Sharing your family history with your physician can help him or her guide you in determining when you should start screenings for breast cancer if you have not been diagnosed with breast cancer. A genetic counselor can also help a patient determine the best course of early intervention if you test positive for BRCA1/2.

If you have been diagnosed, you can see a genetic counselor to review your family history and lifestyle factors to calculate your risk of getting a cancer in your opposite breast over the course of your lifetime.

What remains constant, whether we are talking about a primary breast cancer, or a second primary breast cancer, is early detection and early intervention. These are the tools that give us the best chance of catching most breast cancers in their earliest stages, before they have spread beyond the breast, and are easiest to treat. Getting an annual comprehensive breast exam and a mammogram, and if recommended, an ultrasound or MRI is the best way to protect yourself. These screenings can detect a breast cancer before it can be felt and before you need extensive treatment.


Graeser MK, Engel C, Rhiem K, et al. Contralateral breast cancer risk in BRCA1 and BRCA2 mutation carriers. J Clin Oncol. 2009;27(35):5887-92.

Force: Facing Our Risk of Cancer Empowered. Risk for Second Primary Breast Cancer.

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