Study Explores Cancer Risk Among Those with Family History of Early-onset Breast Cancer
According to the results of a study published in the European Journal of Cancer, individuals with a first-degree family history of early-onset breast cancer (breast cancer diagnosed before the age of 50 in a parent, sibling, or child), are more likely than the general population to develop several types of cancer.
Though several studies have reported an increased risk of breast cancer in individuals with a family history of the disease, there is less information about the risk of other cancers.
To describe the risk of cancer in individuals with a first-degree family history of early-onset breast cancer, researchers conducted a study in Denmark.
Among Danish residents born in 1935 or later, the researchers identified more than 8,000 women who had been diagnosed with breast cancer before the age of 50. Relatives of these women were identified through a Danish population registry. Information about cancer diagnoses in the relatives was collected from the Danish Cancer Registry.
- Relatives of the patients with early-onset breast cancer were more likely than the general population to develop cancers of the breast, ovary, and cervix. Relatives also had an increased risk of developing gallbladder cancer, colon cancer, leukemia, or Hodgkin’s disease before the age of 50, and an increased risk of non-Hodgkin’s lymphoma after the age of 50.
- 39% of the breast cancers and 43% of the ovarian cancers that developed in the relatives could be attributed to their family history of early-onset breast cancer.
- The researchers estimated that BRCA1 or BRCA2 mutations were likely to explain only half of the excess breast cancer cases observed among the relatives.
This study suggests that in addition to increasing the risks of breast and ovarian cancer, having a family history of early-onset breast cancer may also increase the risk of cervical cancer as well as other types of cancer.
Reference: Rawal R, Bertelsen L, Olsen JH. Cancer Incidence in First-degree Relatives of a Population-based Set of Cases of Early-onset Breast Cancer. European Journal of Cancer. 2006;42:3034-3040.