- Genetic tests may overestimate breast cancer risk without considering family history.
- Risk can be as low as 20% for those without close relatives with the condition.
- The psychological impact of misleading genetic test results.
- Insights from over 454,000 individuals in the UK Biobank study.
- Importance of responsible risk communication to prevent unnecessary medical procedures.
Consumer genetic test results, which neglect the consideration of family history, have been causing undue alarm among women regarding their susceptibility to breast cancer, as indicated by researchers.
In cases where women outside clinical settings discover that they carry a disease-causing variation of the BRCA1 or BRCA2 genes, they may be informed of a 60-80% risk of developing breast cancer.
However, an analysis of data from the UK Biobank suggests that the risk could be less than 20% for those lacking close relatives with the condition.
The University of Exeter’s medical school associate professor Leigh Jackson, the study’s primary author, has stressed the potential impact of this misinformation, which might result in unneeded surgical treatments.
The study was published in the journal eClinical Medicine.
According to him, learning that a person has a high genetic propensity for an illness might have a major impact on their level of dread about it and, as a result, their course of action. An 80% risk of breast cancer differs substantially from a 20% risk.”
It is worth noting that NHS clinical geneticists already routinely incorporate family history into their risk assessments, minimizing the likelihood of women proceeding with surgery based on misinformation.
Nevertheless, some women, upon reaching medical clinics, are already strongly inclined toward mastectomy after discovering they carry a BRCA mutation.
Prof. Marc Tischkowitz, the head of medical genetics at the University of Cambridge, who was not involved in the study, commented from a psychological standpoint, “Regardless of what a professional conveys, the initial shock remains, making it challenging for women to be reassured. It’s certainly an issue that we must address.”
In the UK Biobank project, which collects DNA samples and health data from participants and their immediate families, approximately 454,000 people between the ages of 40 and 69 were investigated by the researchers.
Their analysis revealed that carrying a disease-causing BRCA variant was associated with an 18% risk of breast cancer (for BRCA2) and a 23% risk (for BRCA1) by age 60. However, having a close relative with the condition increased the risk to 24% (for BRCA2) and 45% (for BRCA1).
Due to the omission of those who passed away from breast cancer before their time from the cohort, the researchers warned that these numbers could somewhat underestimate the risk.
Until recently, individuals received BRCA results primarily due to clinical visits prompted by symptoms or a family history of the disease.
However, an increasing number of people now become aware of their genetic risk through home DNA testing kits or participation in genetic research, even without a personal connection to breast cancer.
This most recent study emphasizes the importance of family history in determining an individual’s vulnerability by highlighting the effect of secondary genetic variables on the risk carried by BRCA mutations.
The University of Exeter medical school’s Prof. Caroline Wright said, “Our findings go beyond breast and colorectal cancer. Previous risk estimates for genetic diseases have primarily been based on relatively high-risk populations attending specialized clinics, and they may not necessarily apply to the general population.
To minimize undue anxiety and anguish that can need avoidable medical treatments, research is necessary to determine the genuine amount of risk and to appropriately convey this risk.