Aromatase inhibitors (AI) for elderly patients: Efficacy, compliance and safety according to patient age in the BIG 1–98 trial

Abstract

9033 Background: Because elderly patients (pts) are under-represented in clinical trials, care should be taken in extending overall results to that patient group. We compared letrozole (L) with tamoxifen (T) with respect to disease-free survival, treatment compliance, and adverse events (AEs) according to age in the continuous therapy arms of the BIG 1–98 trial. Methods: Between March 1998 and May 2003, 8,028 postmenopausal women with hormone receptor-positive breast cancer were enrolled in the BIG 1–98 trial. This report includes the 4,922 pts allocated to continuous therapy with either T or L for 5 years. Subpopulation Treatment Effect Pattern Plots (STEPP) were used to look at the patterns of differences in disease-free survival and incidences of AEs according to age. In addition, three categorical age groups were defined: “younger postmenopausal” < 65, “older” 65–74, and “elderly” = 75. Cox proportional hazards models were used to compare T and L according to time to first AE, adjusting for relevant pre-existing risk factors. The median follow-up was 40.4 months. Results: STEPP analysis showed the L provided consistent benefit compared with T irrespective of age. Pts 75 and older were less likely to complete trial treatment, but similarly in the two treatment groups. Adjusted treatment comparisons of AEs according to age groups are given below. (T,L: significantly more AEs on T,L; NS: no significant difference) Conclusion: Adjuvant treatment with L had superior efficacy compared with T in all age groups. Physicians should base clinical decisions on the individual patient profile with respect to reduction of risk of recurrence from L as well as existing comorbidities. [Table: see text] No significant financial relationships to disclose.