The Key LARGO study: Building an international resource for glioblastoma epidemiology

Despite decades of epidemiologic research, no glioblastoma risk factors have been identified that explain substantial risk. Prior studies often rely on single- or multi-center recruitment, which is costly and limits generalizability. To address this and increase the diversity of glioblastoma patients in epidemiological research, we have launched the Key LARGO study (NCT06625684, Key Longitudinal Associations with Risk and Glioblastoma Outcomes), an ongoing observational study of glioblastoma patients and their caregivers.

Key LARGO uses web-based enrollment and at-home biospecimen collection via mailed Tasso+ kits for self-collection of blood and serum. Participants complete a detailed, online survey (available in English or Spanish) on life history and health-related quality of life. Primary caregivers are enrolled to help report patient outcomes, including vital status.

Recruitment began on December 10, 2024. As of February 28, 2026, 114 patients and 52 caregivers have consented. Of these, 96 consented to blood collection, 73 received kits, and 52 have returned samples. Eighty-two participants completed the full study survey. Participants were 53% male, with a median age of 54 years (range 24-69) at the time of diagnosis. Diagnoses occurred between 2007 and 2025. Most (96%) identified as White. Seven percent identified as Hispanic or Latino. Blood collection kits have been returned from the United States, Canada, Croatia, Italy, Indonesia, and the United Kingdom.

Key LARGO supports the feasibility of web-based recruitment and remote biospecimen collection in glioblastoma research. The current cohort is best suited for descriptive and hypothesis-generating analyses pending clinical/molecular validation and targeted recruitment.