The number needed to treat (NNT) as a measure of drug efficacy: the case of zoledronic acid for early hormone-responsive breast cancer in the ABCSG-12 trial

Gnant, M, Mlineritsch, B, Schippinger, W, Luschin-Ebengreuth, G, Steger, G, Bjelic-Radisic, V, Jakesz, R, Kubista, E, Marth, C, Greil, R