“PRS is a new type of genetic testing and genetic information that we haven’t been able to offer before because we’ve only been focusing on single genes,” says Dr Yanes, who conducted the study as part of her PhD at UNSW, and is now with University of Queensland.

“The vast majority of women who get screened for the BRCA genes come back negative, but that doesn’t always mean there’s no breast cancer risk. PRS looks much more broadly at variants in your DNA.”

A genetic variant is a small change to the base molecules that make up the DNA. On their own, they don’t necessarily mean greater risk. But the more variants found in the DNA, the greater the PRS.

“Past studies have shown that getting a PRS for breast cancer has the potential to improve health outcomes,” says Dr Yanes.

“But this is the first time that we have looked at how women who receive this information react. Does it cause more stress, or does it reduce it, and can it bring about positive behaviours in women who have either already been diagnosed with it or have a family history of breast cancer?”

Of the 208 study participants, 165 women (80 per cent) agreed to receive their PRS while the remaining 43 participants declined to be informed.

Among the women who agreed to be told their scores (dubbed ‘receivers’), 104 were given a high-risk score, while the remaining 61 were assessed as low-risk.

Not surprisingly, the study found that women with higher PRS experienced slightly more distress and anxiety upon receiving their result than those with a low PRS, “but it wasn’t really that big a gap to actually warrant additional psychological support,” Dr Yanes says.

Regrets

But surprisingly, when the researchers compared the psychological outcomes of the women who opted to receive their PRS with those who declined, more women in the latter group reported regret about their original decision not to find out.

“Those who had received the results reported basically minimal regret. In fact, more than half of them actually had a score of zero, which means no regret at all,” says Dr Yanes.

“But the average regret score for those who didn’t receive that PRS result was around 38 out of 100 when compared to an average score of just 9 in the ‘receivers’ group.”

The researchers gathered the results in follow-up questionnaires at two weeks and 12 months after calculating the PRS scores, and they measured the regret using a validated method known as the Decision Regret Scale.

Among the women who declined to find out their PRSs, reasons included being “happy with their lives right now”, or that they were “already aware of breast cancer risk” and that the “test will not tell them when they will develop breast cancer”. Other reasons included not being able to attend the appointment in person and concern over how they would handle it emotionally.

Dr Yanes says the results will help clinicians and genetic counsellors to equip women with the tools to make an informed decision about whether or not to get a PRS result.

“We want doctors to be able to provide women with clear information outlined in decision aids that explains what the PRS is and the type of access women have to these genetic services,”> Dr Yanes says.

“What we don’t want is that people decline information out of fear, or aren’t able to make an informed decision because they may not fully understand the information or what the implications for them are.”

Following on from the study, Dr Yanes will provide clinicians around the country with best practice guidelines on how to deliver personalized cancer risk management to women undergoing PRS genetic testing.

The research was published recently in Genetics in Medicine.

Source: Eurekalert