Inflated Risks From Genetic Testing Could Lead to Unnecessary Breast Surgery
Women could be opting to have unnecessary surgery to avoid breast cancer, after genetic test results.
Complete the form below to unlock access to ALL audio articles.
Women could be opting to have unnecessary surgery to avoid breast cancer, after being told they are at high risk from genetic test results which do not take family history into account.
The authors of new research led by the University of Exeter have warned that women who discover, outside of a clinical setting, that they carry a disease-causing variant in one of the BRCA genes (BRCA1 or BRCA2) may be told their risk of breast cancer is 60-80 per cent. In fact, the risk could be less than 20 per cent if they do not have a close relative with the condition.
The warning has emerged in a paper published today in the Lancet journal eClinical Medicine. Until recently, women who received BRCA results did so because they attended clinic due to symptoms, or a family history of disease. The likelihood of certain BRCA variants causing breast cancer has been calculated based on this already high-risk group. However, many people now pay for home DNA testing kits, or are given results as part of taking part in genetic research, without ever having any personal link with breast cancer. The new research, funded by the Medical Research Council, was conducted to get a better idea of the true risk level of these BRCA variants in the general population.
The authors analysed more than 454,000 participants recruited between the ages of 40 and 69 in the UK Biobank study, which collects DNA samples and asks participants to report illness in themselves as well as parents and siblings. They found that simply carrying a disease-causing BRCA variant was linked to a breast cancer risk of 18 per cent (for BRCA2) and 23 per cent (for BRCA1) by age 60. Having a close relative who has had the condition elevated the risk to 24 per cent (for BRCA2) and 45 per cent (for BRCA1) .
The research team found a similar result when looking at genetic risk of Lynch syndrome, a genetic condition which increases the risk of colon cancer and some other cancers. The authors also concluded that genetic screening for these conditions in the general population could result in large numbers of people being exposed to needless scans or further procedures.
Co-author Professor Caroline Wright, of the University of Exeter Medical School, said: “Our findings will not just apply to breast and colorectal cancer. 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. This finding has important ramifications for population screening using genome sequencing. 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.”
The paper is entitled ‘Influence of family history on penetrance of hereditary cancers in a population setting’, and is published in eClinical Medicine.
If you’re given a high genetic risk of any disease outside of a clinical setting, we’d advise you to speak to your doctor, who will be able to take into account a range of factors including family history to assess whether the risk may be worth investigating further.
Reference: Jackson L, Weedon M, Green H, et al. Influence of family history on penetrance of hereditary cancers in a population setting. eClinicalMed. 2023. doi: 10.1016/j.eclinm.2023.102159
This article has been republished from the following materials. Note: material may have been edited for length and content. For further information, please contact the cited source.