Characterisation and classification of oligometastatic disease: a European Society for Radiotherapy and Oncology and European Organisation for Research and Treatment of Cancer consensus recommendation

Guckenberger, M; Lievens, Y; Bouma, Ab; Collette, L; Dekker, A; Desouza, Nm; Dingemans, Amc; Fournier, B; Hurkmans, C; Lecouvet, Fe; Meattini, I; Romero, Am; Ricardi, U; Russell, Ns; Schanne, Dh; Scorsetti, M; Tombal, B; Verellen, D; Verfaillie, C; Ost, P