1. Age > 50 Abstract Background Limited data exists regarding outcomes and AT benefit/toxicity in Y pts with stage II and III CC. We examined overall survival (OS), disease free survival (DFS), recurrence free interval (RFI) and AEs in the 33,574 pt ACCENT dataset. Methods Individual pt data from 24 randomized Phase III clinical trials (CT) was obtained for survival outcomes, and 10 CT for AE outcomes. Two age-based cut-offs were used to define Y pts, age < 40 and < 50. Cox models stratified by study and adjusted for gender and stage. AT benefit analyses were limited to 9 CT testing 5-FU/LV or Lev vs control (7 CT) or oxaliplatin+5-FU/LV vs 5-FU/LV (2 CT). Results 1758 (5.2%) pts were age 0.35). Y pts had improved OS and DFS (Table), even when restricting to age 50, interaction p=0.19). No clinically meaningful differences in AEs were observed between ages. Conclusions Among pts on CT, Y (age 30-50) stage II and III CC pts had similar RFI and AT benefit as older pts, with no clinically meaningful differences in AEs. Y pts have improved OS and DFS, likely primarily due to to fewer competing causes of death. Adjuvant therapy is beneficial for CC pts aged 30-50 meeting typical CT eligibility criteria. ACCENT Initially established in 2003, to validate disease-free survival (DFS) as an endpoint in adjuvant colon cancer Individual patient data from 24 large adjuvant randomized clinical trails, 33,574 patients Jointly owned by all contributors ACCENT collaborators S Wieand, G Yothers, M O’Connell, N Wolmark – NSABP J Benedetti, C Blanke – SWOG R Labianca – Ospedali Riuniti (Italy) D Haller, P Catalano, A Benson – ECOG C O’Callaghan – NCIC JF Seitz – University of the Mediterranean (France) G Francini – University of Siena (Italy) A de Gramont, T Andre – GERCOR R Goldberg, L Saltz, J Meyerhardt, N Jackson – CALGB M Buyse – IDDI (Belgium) R Gray, D Kerr – QUASAR A Grothey, S Alberts, B Bot, E Green, Q Shi –Mayo Clinic C Twelves -University of Bradford (UK) J Cassidy – University of Glasgow (UK) F Sirzen – Roche ; L Cisar - Pfizer E Van Cutsem –University Hospital Gasthuisberg (Belgium); A Sobrero - Ospedale San Martino (Italy) Discussion Even restricting comparison to patients < 50 vs 50-60, p = 0.0061 (HR=1.08) for improved DFS for < 50 Detailed data on dosing not available Conclusions Among patients on clinical trials, younger (age 30-50) stage II and III colon cancer pts had similar adjuvant therapy benefit as older patients No clinically meaningful differences in AEs were present between age groups Younger pts have improved OS and DFS, likely primarily due to fewer competing causes of death Adjuvant rx is beneficial for colon cancer patients aged 30- 50 meeting typical clinical trials eligibility criteria Benefits and adverse events in younger (age <50) vs older patients receiving adjuvant chemotherapy for colon cancer: Findings from the 33,574 patient ACCENT dataset Daniel Sargent, Greg Yothers, Erin Green, Charles Blanke, Michael O’Connell, R Labianca, Archie Bleyer, A DeGramont, and David Thomas as a joint project of the LIVESTRONG Young Adult Alliance and the ACCENT collaborative group Methods Analyses of individual patient data Endpoints: Primary: Disease Free Survival (PFS) Secondary: Overall Survival (OS) Grade ≥ 3 adverse events (AE) Cox regression models adjusted by age and gender, stratified by study: Effect of age with cut points of < 40 and < 50 Age-by-treatment interaction to assess relative benefit in 9 trials that demonstrated adjuvant therapy benefit Baseline Characteristics by Age ACCENT: Trials included DFS: Experimental vs Control - 9 Studies w/ Treatment Benefit Age Cutoff – 50 Age Cutoff – 40 Adverse Events by Age Disease Free Survival – All Studies Age Cutoff – 40 Time to Recurrence & Overall Survival – All Studies Age Cutoff – 50 OS: Experimental vs Control - 9 Studies w/ Treatment Benefit Age > 40 Age < 50 Age < 40 Age > 40 Age < 50Age > 50 Age < 40