Evaluating the return of additional findings from the 100,000 Genomes Project: A mixed methods study exploring participant experiences of receiving secondary findings from genomic sequencing.

Purpose: 100,000 Genomes Project participants could consent to receive additional findings (AFs) for variants associated with susceptibility to cancer and familial hypercholesterolemia (FH). Here we evaluate stakeholder experiences to inform clinical practice.

Methods: Mixed-methods study conducted at 18 sites across England that comprised a cross-sectional survey and interviews with participants who received a positive AF (PAF), and interviews with participants who had no AFs (NAF).

Results: There were 146 surveys followed by 35 interviews with PAF participants, and 29 interviews with NAF participants. Surveys found that PAF results were seen as useful and would influence health management (82%). Most (90%) had shared their result with family members. Experiences differed by PAF type; cancer PAF participants were often initially shocked and anxious, and found telling family members challenging compared to participants with an FH PAF. Whilst most experiences of NAF results were positive, some misunderstandings were identified. Participants supported returning AFs when offering genome sequencing.

Conclusion: Patient experiences of receiving AFs were primarily positive and there is support for offering AFs routinely. Considerations for offering AFs in clinical practice include adapting approaches tailored to individual conditions and greater support for people with a NAF result.