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[9 min read] Genetic testing motivates behaviour changes in at-risk melanoma patients
Would genetic testing motivate behaviour changes in patients at high risk of melanoma? Melanoma is one of the most severe types of skin cancer, with around 14,000 new cases and 2,000 deaths in Australia each year.
A new study led by researchers the University of Utah investigated whether genetic testing would motivate people at risk of developing melanoma to alter their behaviour in order to reduce their risk.
The study attempted to understand whether a genetic test result adds value over and above what can be achieved by patient counselling alone. The authors said that since a genetic test result is concrete and highly personalised, this might be more motivating for difficult behaviour change than information about risk based just on family history.
Published this month in Genetics in Medicine, the study focused on families with a high risk of melanoma. Individuals enrolling in the study had three or more family members diagnosed with melanoma. Participants between the ages of 16-70 were recruited from melanoma-prone families of two types: Families with a known cancer-causing gene called CDKN2A and families with comparably high rates of melanoma but no identified CDKN2A mutation.
Researchers previously discovered that individuals who carry an inherited mutation in the CDKN2A gene are rare, but those individuals have a risk of up to 76 per cent of developing melanoma in their lifetime.
The study’s authors said that all melanoma has a strong genetic component, but individuals with a strong family history are at extremely high risk. They are ideal candidates for prevention and early detection measures, and so making a few relatively simple changes could save their lives.
Each participant received individual counselling from a licensed genetic counsellor at the University of Utah. These sessions consisted of a review of family medical history and education about melanoma risk factors, including exposure to environmental ultraviolet radiation (UVR) and genetic predisposition. Participants also received pretest counselling and basic information about melanoma and genetic testing. Members of families known to carry the CDKN2A mutation then were assessed through clinical genetic testing, while subjects from families with no known CDKN2A mutations received information about risk based on family history alone. All participants received identical recommendations for reducing sun exposure.
The multidisciplinary research team included genetic counsellors, psychologists, a dermatologist, photo-biologists and an atmospheric scientist. The team examined changes in sun exposure following genetic counselling and test reporting. They used objective measures to track participants, including a special wristwatch-like device to measure UVR and a laser that measures skin colour to assess the degree of tanning.
The results showed that genetic counselling about highly elevated melanoma risk, both with and without test reporting, led to sustained reductions in UVR exposure. Additionally, the results provided evidence of a unique benefit to participants who received genetic testing: those who learned they carry the CDKN2A mutation showed reduced exposure to daily UVR the month following genetic counselling, and showed lighter skin pigmentation one year later.
The study’s authors said that the results support the use of melanoma genetic testing to motivate people to adopt risk-reducing behaviours.
Previously, it was thought genetic testing wouldn’t matter because members of high-risk families already knew about their risk and were already being advised to reduce their sun exposure. This study shows that genetic testing, paired with counselling about familial risk and its management, can be a useful tool to motivate cancer prevention behaviour.
Researchers are confident in these results as they were able to use state-of-the-art objective measures of sun exposure. They found that those with the CDKN2A mutation did not simply wish to limit sun exposure – rather, information about personal risk resulted in significant reductions in the levels of sun exposure during the year following genetic counselling.
The team said their next goal is to better understand how knowledge of having a high risk for cancer leads to health-promoting changes in behaviour rather than leading to debilitating responses. They also seek to improve education so the public understands a tan is a sign of skin damage that can lead to melanoma.
Findings from this study and future work will help guide the development of counselling techniques, including optimal follow-up and integration into a patient’s routine healthcare program. The authors noted that genetic testing is becoming more common in healthcare, but a lot is still unknown about how and when to deliver this information in a manner that promotes healthy behaviour changes.