Data from over 450,000 UK Biobank participants show the importance of considering family history alongside genetics before making decisions on invasive preventative surgeries.
Summary
Data from more than 450,000 UK Biobank participants have revealed that women who carry a ‘breast cancer gene’ have a lower cancer risk than previously thought – if their parents or siblings have not had the disease. “Up to 80% risk of developing breast cancer is very different from 20%,” said the study’s lead researcher Leigh Jackson. “That difference could well influence the decision you make around whether you have invasive [preventative] surgery.”
Women who carry a ‘breast cancer gene’ have a lower cancer risk than previously thought – if their parents or siblings have not had the disease.
Medical and genetic data from more than 450,000 UK Biobank participants have revealed just how important family history is when understanding the likelihood of developing breast cancer. This could help women with ‘high-risk genetics’ to decide if they want to have preventative surgeries, such as a mastectomy, to reduce their cancer risk.
The BRCA genes help healthy cells survive and prevent the growth of cancerous ones. Women who have an alteration in one of the two BCRA genes were thought to have at least 65% risk of developing breast cancer, compared with a 15% risk for people whose genes function normally.
Researchers now discovered that actual figure might be lower: 23% of women younger than 60 who carry one altered gene went on to develop breast cancer. This proportion went up to 45% for women with one of the altered genes who also had a close relative with the disease.
For almost all genes that lead to a cancer susceptibility in adulthood, the variable lifetime risks are clearly influenced by the burden of the family history, as well as personal risk factors like reproductive status, contraceptive use, weight, and lifestyle.
Dr Ora Karp Gordon, Saint John’s Cancer Institute, US
Risk runs in the family
The team looked at UK Biobank participants’ genetic data, hospital and cancer records as well as and self-reported information on health and family history. “For almost all genes that lead to a cancer susceptibility in adulthood, the variable lifetime risks are clearly influenced by the burden of the family history, as well as personal risk factors like reproductive status, contraceptive use, weight, and lifestyle,” Ora Karp Gordon, a geneticist at Saint John’s Cancer Institute, US, who is independent of the study’s team, told Healthline.
The study’s lead researcher Leigh Jackson from the University of Exeter, UK, hopes this discovery will support people in making treatment decisions. “Being told you are at high genetic risk of disease can really influence levels of fear of a particular condition and the resulting action you may take,” explained Jackson to The Telegraph.
“Up to 80% risk of developing breast cancer is very different from 20%,” he added. “That difference could well influence the decision you make around whether you have invasive breast surgery.”
“All risk estimates of genetic disease have so far largely been based on relatively high-risk groups who attend specialist clinics, so they will not necessarily translate to the general population” Jackson’s colleague and study team member Caroline Wright told The Telegraph. “We need to ensure we are carrying out research to find the true risk level, and also to be responsible in how we communicate risk, to avoid unnecessary fear and distress, which may lead to avoidable procedures.”