Abstract
BACKGROUND
This study evaluated the impact on overall survival (OS) of 2 versus 5 years adjuvant tamoxifen in early breast carcinoma patients after 12 years of follow‐up.
METHODS
Women with breast carcinoma T1–3, N0–3, M0, aged 50–70 years, were eligible for this multicenter randomized Phase III trial. Patients event‐free after 2 years of tamoxifen therapy (TAM) were randomly assigned to stop or continue TAM (20 mg/day) for an additional 3 years. The primary endpoint was disease‐free survival. Secondary endpoints included OS and toxicity.
RESULTS
From 1989 through 1996, 1901 patients were randomly assigned either to stop treatment (n = 958) or to continue TAM (n = 943). Overall, 98% of patients alive at the previous report (n = 1611) had updated information about OS, of whom 549 had died. The median duration of postrandomization follow‐up was 115 months (interquartile range, 86–137). No statistically significant differences between the two arms were detected in the whole population (hazard ratio [HR], 1.02; 95% confidence interval [CI], 0.86–1.22) and in estrogen receptor (ER)‐positive patients (HR, 0.90; 95% CI, 0.72–1.13). In the latter group, survival curves started to diverge after 90 months, showing a trend in favor of the 5‐year arm. In younger (age ≤55 yrs) ER‐positive patients longer TAM was associated with a 44% decrease in the risk of death (HR, 0.56; 95% CI, 0.31–1.00), while no clear benefit was documented in women older than 55 years of age (HR, 0.98; 95% CI, 0.77–1.25).
CONCLUSIONS
The benefits of longer TAM on OS start to emerge only after 9 years from diagnosis and seem to be more relevant in younger ER‐positive women. Cancer 2005. © 2005 American Cancer Society.