continuous exponential growth, with these doubling times, it would take roughly 8–16 years for a single cancer cell to grow into a clinically detectable tumor (Spratt et al., 1995; von Fournier et al., 1980). It should be also noted that breast cancers in women > 50 years old grow more slowly than those in younger women (Peer et al., 1993; Spratt et al., 1996).
