218PFeasibility study of using an app-based mHealth group challenge to improve physical activity (PA) and fatigue after breast cancer (BC). (13th May 2019) - Martin, E; Di Meglio, A; Charles, C; Ferreira, A R; Gbenou, A; Blond, M; Fagnou, B; Pistilli, B; Saghatchian, M; Vaz-Luis, I