Women diagnosed with breast cancer have a higher risk of getting a new breast cancer than women who have never had breast cancer [207-210].
A new breast cancer is called a second primary breast cancer.
Unlike a recurrence, which is the return of the first breast cancer, a second primary tumor is a new cancer unrelated to the first.
Women treated with lumpectomy (also called breast conserving surgery) for their first breast cancer can get a second primary cancer in either breast.
Women treated with mastectomy for their first breast cancer can only get a new cancer in the other breast (except in rare cases).
After either type of surgery, the risk of a second breast cancer increases over time.
About 5 percent of women will get a second breast cancer within 8 years of their initial diagnoses [207-208].
After about 25 years, up to 14 percent of women will have been diagnosed with a second breast cancer [207,211].
Women whose first breast cancer was hormone receptor-negative may have a higher risk of a second primary breast cancer compared to those whose first breast cancer was hormone receptor-positive [209,212-215].
Ductal carcinoma in situ (DCIS) is a non-invasive breast cancer. Abnormal cells grow within the milk ducts of the breast, but they don't spread to nearby tissues.
DCIS is non-invasive, but without treatment, the abnormal cells could progress to invasive breast cancer over time.
Left untreated, about 40-50 percent of DCIS cases may progress to invasive breast cancer . (These numbers are estimates.) Higher grade DCIS may be more likely than lower grade DCIS to progress to invasive cancer if left untreated.
At this time, health care providers can't predict which cases of DCIS will progress to invasive breast cancer and which will not. So, almost every case is treated.
After treatment for DCIS, there's still a small risk of [217-219]:
Learn more about treatment for DCIS.
Learn more about DCIS and the risk of invasive breast cancer.
Learn more about the anatomy of the breast.
A personal history of certain other cancers can increase the risk of breast cancer.
Women who had Hodgkin's disease in childhood or early adulthood have an increased risk of breast cancer [220-225]. They are about 5-12 times more likely to get breast cancer than women who never had Hodgkin's disease .
By age 50, women who had Hodgkin's disease in childhood or early adulthood have about a 35 percent chance of developing breast cancer .
Breast cancer risk appears to be greater among women treated with radiation therapy for their Hodgkin's compared to those treated with chemotherapy alone [220,222,224].
Women treated for Hodgkin's at later ages (even with radiation therapy) don't appear to have an increased risk of breast cancer .
Women who have had ovarian cancer have an increased risk of breast cancer . This is likely due to genetic factors.
Women who have an inherited BRCA1 or BRCA2 gene mutation have an increased risk of breast cancer and ovarian cancer [24,148].
Some rare gene mutations can lead to genetic syndromes that increase the risk of more than one type of cancer, including breast cancer.
A personal history of another cancer (such as colon, thyroid or uterine cancer) that's related to a rare genetic syndrome can increase the risk of breast cancer [154,226-227].
Learn more about inherited gene mutations.
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