RT Journal Article SR Electronic T1 675 Evaluation of a web-based intervention for patients with gestational trophoblastic disease: a randomized controlled trial JF International Journal of Gynecologic Cancer JO Int J Gynecol Cancer FD BMJ Publishing Group Ltd SP A345 OP A345 DO 10.1136/ijgc-2021-ESGO.610 VO 31 IS Suppl 3 A1 Frijstein, M A1 Blok, L A1 Ten Kate Booij, M A1 Eysbouts, Y A1 Van Trommel, N A1 Sweep, F A1 Massuger, L A1 Van Hamont, D A1 Schreuder, H A1 Smink, M A1 Molkenboer, J A1 Vencken, P A1 Ottenvanger, N A1 Lok, C YR 2021 UL http://ijgc.bmj.com/content/31/Suppl_3/A345.1.abstract AB Introduction/Background*Gestational Trophoblastic Diseases (GTD) comprise a group of rare diseases originating from the trophoblast, affecting women of child-bearing age. Providing optimal information to patients with a rare disease is challenging, because of the small number of patients and limited clinical expertise of many healthcare professionals. We investigated whether a web-based interactive intervention influences levels of distress, illness-perception and knowledge in women with GTD.Methodology Sixty-nine patients diagnosed with GTD were enrolled in a multicenter randomized controlled trial using online questionnaires in the Netherlands between 2017-2019. Patients were randomized between direct access or postponed access to an online tool on GTD intended to increase knowledge on this rare condition and formulate questions prior to consultation with a medical specialist.Result(s)*Patients using the online tool had higher level of knowledge compared to the control group (p = 0.006), and were satisfied with the intervention (92%). No differences in levels of anxiety, depression, distress and illness-perception were observed between the groups.Conclusion*The online tool was valuable for newly-diagnosed GTD patients. The improvements in knowledge after digital education, indicates that this tool can be used as an effective method of supporting GTD patients’ informational needs without causing extra distress.