- The risk of breast cancer in women is 76% higher if their mother or sister has had it.
- People without a family history could have surgery to protect themselves from cancer
Women need to be aware of unnecessary mastectomies due to the ‘Jolie effect,’ experts say.
Women with mutations in the BRCA1 gene, such as Hollywood actress Angelina Jolie, and the related BRCA2 gene, are at greater risk of breast cancer.
But one study found that their risk is 76 percent higher if they also have a mother or sister with breast cancer.
Experts worry that women do not realize that their risk of breast cancer is much higher if they have a family history, like Ms. Jolie, who had a mastectomy to reduce her risk of developing cancer.
Those without a family history may end up having surgery to protect themselves from cancer, making an important decision without realizing that they are much less likely to get it.
Women with mutations in the BRCA1 gene, such as Hollywood actress Angelina Jolie (pictured in 2021), and the associated BRCA2 gene, are at greater risk of breast cancer.
The evidence comes from a study of 450,000 Britons, aged 40 to 70, who underwent genetic testing as part of the UK Biobank health study.
Of these, 230 had a BRCA1 gene mutation, 78 of whom also had a mother or sister with breast cancer.
When these people were followed until age 60, nearly 45 percent of them with the genetic mutation and a family history developed breast cancer.
But only 23 percent of women with the mutation got breast cancer before age 60 if they didn’t also have a close family history.
Researchers say women should pay close attention to these numbers, as the rise in take-home genetic testing kits means many can now find out they have a mutation in one of the BRCA genes .
Experts are concerned about the decisions that could be made by these women, who would not have been eligible for genetic testing through the NHS unless they had breast or ovarian cancer, or a member of their family has one of these cancers and a known BRCA mutation.
Hollywood star Ms Jolie (pictured in 2011) had a mastectomy to reduce her risk of developing cancer.
Researchers say women should pay close attention to the numbers because the increase in genetic testing kits done at home means many can now find out they carry a mutation.
Dr Leigh Jackson, who led the study at the University of Exeter, said more women were choosing breast cancer surgery, particularly since Angelina Jolie, 48, shared her experience.
But he added: “Being told that you are at high genetic risk of disease can really influence levels of fear of a particular disease and the actions you can take as a result.
“We strongly recommend that anyone communicating cancer risk do so based on a detailed family history, not just genetics.”
The study, published in the journal Lancet eClinical Medicine, indicates that estimates of breast cancer risk from genetic mutations such as BRCA1 and BRCA2 may be misleadingly high for people without a family history of the disease.
Indeed, people with a family history are likely at higher risk of unknown mutations in genes other than BRCA genes.