Introduction/Background 70% UK adults use social media and 60% seek health-related information on the internet. There is increasing access/awareness of genetic testing and risk-management for hereditary breast & ovarian cancer (HBOC) and Lynch syndrome (LS) cancer susceptibility genes. Social media activity on HBOC/LS has not been quantified/characterised. We undertake the first comprehensive review of social media activity on HBOC/LS across major platforms.

Methodology An AI-powered social media listening platform accessed and interrogated public posts on X(Twitter), Instagram, Facebook, and Reddit. Keyword searches collated all posts regarding: (a)HBOC/LS; (b)germline genetic-testing(GT); (c)risk-reducing surgery(RRS); and (d)pre-implantation genetic-diagnosis(PGD). Number of posts, platform distribution, engagement (likes/comments/shares), and account follower were extracted. Author data(individual/organisation) and content were manually extracted and evaluated from representative samples.

Results Searches yielded 51,786 posts (HBOC/LS:43,764; GT:4961; RRS:2933; PGD:128) between February-May 2023. X was more commonly used across HBOC/LS and GT (65.9% HBOC/LS), while Reddit for PGD(65%) and RRS(34%) posts. BRCA1/2 posts were up to 14.5x more common than LS posts. Only 1.6% of RRS posts were about LS. HBOC/LS posts made by individuals had higher views, likes, and retweets on X than posts by organisations despite having fewer followers (median followers= 754 vs 2019). 86% of posts by professionals (healthcare professionals/researchers) were on X. 58% of posts related to professional activity, delivery of healthcare/research. Higher proportion of Instagram posts related to personal experiences/testimonials/lifestyle/raising awareness by lay-people. Academic institutions had the highest X followers (median=3450), while patient/public support-groups had the highest Instagram followers (median=4636).

Conclusion Our findings are relevant for planning public/patient awareness/engagement/education, and information dissemination. For HBOC/LS, X appears the preferred platform for disseminating professional activity, while Instagram has proportionally higher usage by lay-people. Professionals can increase public reach/access to their posts by using platforms in addition to X. Posting through different account types (individual or organisational) can leverage greater engagement or reach respectively.

Disclosures Ashwin Kalra declares funding from Barts Charity.

Samuel Oxley declares grant funding from Rosetrees Trust.

Ranjit Manchanda declares grant funding from the British Gynaecological Cancer Society, Barts & the London Charity, Eve Appeal, GSK, Rosetrees Trust, NHS Innovation Accelerator (NIA), and Yorkshire Cancer Research, NHS England. He has received an honorarium for grant review from Israel National Institute for Health Policy Research and honorarium for advisory board membership from Astrazeneca/MSD/EGL/GSK. He has participated in a GSK sponsored speaker's bureau.