[102] The benefits of letrozole in postmenopausal women with early stage breast cancer who have had five years of tamoxifen are independent of age.
Muss HB, Tu D, Ingle JN, Martino S, Robert NJ, Pater JL, Whelan T, Palmer MJ, Piccart MJ, Shepherd LE, Pritchard KI, He Z, Goss PE.. University of Vermont Cancer Center, Burlington, VT; Queens Universtiy, Kingston, ON, Canada; Mayo Clinic Cancer Center, Rochester, MN; University of Southern California, Los Angeles, CA; Fairfax Hospital, Fairfax, VA; McMaster University, Hamilton, ON, Canada; Jules Bordet Cancer Institute, Brussels, Belgium; University of Toronto, Toronto, ON, Canada; Massachusetts General Hospital, Boston, MA
Background: MA17 randomized 5187 postmenopausal patients (pts) (median age 62 years (yrs)) with ER+ early breast cancer completing 5 yrs of tamoxifen to letrozole (LET) 2.5 mg or placebo (PLAC) daily x 5 years (Goss, JNCI 2005; 97:2362). At 30 months median follow-up the hazard ratio (HR) for disease-free survival (DFS) was 0.58 (p=0.00004) and for distant disease-free survival (DDFS) 0.60 (p=0.002). OS was significantly improved only in the node+ cohort (HR=.61, p=.04). This analysis was performed to determine whether there were age dependent differences in DFS, OS, toxicity or quality of life (QOL).
Materials and Methods: Randomized pts were divided into 3 age groups: <60 yrs (n=2152); 61-69 yrs (n=1694); and 70+ yrs (n=1323). Chi-square was used for univariate analyses for associations between age and clinical characteristics and ANOVA for multivariate (MV) analyses to identify independent characteristics associated with age. Times to events were analyzed by log-rank tests and Cox models. QOL was assessed using the SF-36 instrument.
Results: In MV analysis more younger pts were N+, had prior chemotherapy and had breast conservation compared to older pts. There was no age
related difference in DFS or DDFS for the overall study population. OS was significantly shorter in 70+ pts possibly due to non-breast cancer deaths but N+ pts 70+ had a significant improvement in OS on LET (p=.04). Subgroup analyses by age comparing LET and PLAC at 4-years for DFS and OS is tabulated below. Statistically significant benefits are only seen in the <60 subgroup, but the HRs for all subgroups are less than 1.0 and the interaction between treatment and age (Cox model) was not significant for any endpoint. Toxicities by age for LET and PLAC showed no difference in pts 70+. QOL at 36 months for pts 70+ was similar for LET and PLAC.
Discussion: For pts 70+ in good health LET has similar benefits as in younger pts without any increase in toxicity when compared to PLAC; older pts should also be considered for LET after 5 years of tamoxifen.
| Group | Letrozole | Placebo | HR | p |
| <60 | 94.5 | 90.2 | 0.46 | .0004 |
| 61-69 | 93.8 | 89.1 | 0.68 | .078 |
| 70+ | 94.7 | 90.2 | 0.67 | .12 |
| Group | Letrozole | Placebo | HR | p |
| <60 | 97.6 | 97.3 | .78 | .56 |
| 61-69 | 96.7 | 95.8 | .75 | .56 |
| 70+ | 90.8 | 90.6 | .82 | .44 |
Thursday, December 14, 2006 5:00 PM
Poster Discussion Session I: Aromatase Inhibitors (5:00 PM-7:00 PM)