“…Variability of PFS outcomes has been the subject of previous studies [van de Beek et al, 1992;Hansen et al, 1997;Madsen et al, 1995;Rosier et al, 1995;Tammela, 1999;Witjes et al, 1996]. Variability of PFS outcomes has been the subject of previous studies [van de Beek et al, 1992;Hansen et al, 1997;Madsen et al, 1995;Rosier et al, 1995;Tammela, 1999;Witjes et al, 1996].…”