A total of 165 participants had an event involving
disease recurrence or the occurrence of
contralateral breast cancer (67 in the letrozole
group and 98 in the placebo group). Among
these patients, 55 in the letrozole group and 68
in the placebo group had recurrent breast cancer,
and 13 and 31, respectively, had contralateral
breast cancer (Table 2). The Kaplan–Meier curves
for disease-free survival are shown in Figure 1A.
The rate of 5-year disease-free survival was 95%
(95% confidence interval [CI], 93 to 96) in the
letrozole group and 91% (95% CI, 89 to 93) in
the placebo group. The hazard ratio involving
disease recurrence or the occurrence of contralateral
breast cancer with letrozole versus placebo
was 0.66 (95% CI, 0.48 to 0.91; P = 0.01).