External validation of PREDICT Breast v3.1 for overall survival in international cohorts, including young and invasive lobular subgroups. - Verheul EM; Doornkamp F; Petrov I; Siesling S; Lingsma HF; Koppert LB; Vreven LWA; Voogd AC; Karsten MM; Doppelbauer L; Gebert P; Kiani N; et al. (Breast cancer research and treatment, 2026)