Breast cancer survivors have an increased risk of getting a new breast cancer compared to women who have never had breast cancer [184-185]. A new 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 treatment, the risk of a second breast cancer increases over time. Close to five percent of women will get a second breast cancer within eight years of their initial diagnoses [184-186]. After about 25 years, up to 14 percent of women will have been diagnosed with a second breast cancer [184-187].
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 [188-190].
Ductal carcinoma in situ (DCIS) is a non-invasive breast cancer. In DCIS, many abnormal cells grow within the ducts of the breast (see the structure of the breast).
DCIS is non-invasive, but without treatment, the abnormal cells could turn into invasive breast cancer over time. Left untreated, about 20 to 30 percent of low grade DCIS will progress to invasive breast cancer . Higher grade DCIS may be more likely to turn into invasive cancer if left untreated.
At this time, health care providers cannot predict which cases of DCIS will progress to invasive breast cancer and which will not. Because DCIS might turn into invasive breast cancer, almost every case is treated. Treatment includes surgery, with or without radiation therapy and/or hormone therapy. Learn more about treatment for DCIS.
DCIS survivors have an increased risk of DCIS in the opposite breast as well as an increased risk of invasive cancer in either breast [191-193].
Learn more about DCIS and the risk of developing invasive breast cancer after DCIS.
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 are about 15 to 25 times more likely to get breast cancer than women who never had Hodgkin's disease [194-197]. This risk appears to be greater among women treated with radiation therapy for their Hodgkin's compared to those treated with chemotherapy alone [195-196]. Women who were treated for Hodgkin's at later ages (even with radiation therapy) do not appear to have an increased risk of breast cancer .
Women who have had ovarian cancer appear to have an increased risk of breast cancer . This is likely related to genetic factors. Women who have an inherited mutation in the BRCA1 or BRCA2 gene have an increased risk of both breast and ovarian cancer [26,119].
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 is related to a rare genetic syndrome can increase the risk of breast cancer [198-200].
Learn about inherited gene mutations.
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