Summary Cognitive function in postmenopausal women receiving letrozole
or tamoxifen as adjuvant endocrine treatment was compared during the
fifth year of treatment in a substudy of the BIG 1-98 trial. In BIG 1-98
patients were randomized to receive adjuvant A) 5-years tamoxifen, B)
5-years letrozole, C) 2-years tamoxifen followed by 3-years letrozole,
or D) 2-years letrozole followed by 3-years tamoxifen. The primary
comparison was the difference in composite score for patients taking
letrozole (B+C; N=65) versus tamoxifen (A+D; N=55). The patients taking
letrozole had better overall cognitive function than those taking
tamoxifen (difference in mean composite z-scores =0.28, p=0.04, 95%
CI:0.02, 0.54, Cohen's D = 0.40 indicating small to moderate effect). In
this substudy, breast cancer patients taking adjuvant letrozole during
the fifth year of treatment had better cognitive function than those
taking tamoxifen, suggesting aromatase inhibitors do not adversely
impact cognition compared with tamoxifen. Testolone powder
The Breast International Group (BIG) 1-98 and Arimidex, Tamoxifen Alone
or in Combination (ATAC) trials demonstrated that, in postmenopausal
women with hormone receptor positive (HR+) early-stage breast cancer, 5
years of initial adjuvant endocrine therapy with letrozole or
anastrozole is superior to tamoxifen. With expected generic availability
of anastrozole in July 2010 and letrozole in June 2011, there may be
financial pressures prior to letrozole's generic availability to start
treatment- patients on anastrozole vs. letrozole or to switch patients
already receiving letrozole to anastrozole. A Markov model was used to
estimate cost per quality-adjusted life-year (QALY) gained with
letrozole vs. anastrozole from the US healthcare system perspective.
Cost effectiveness was examined separately in treatment- patients and in
patients already receiving letrozole. For the latter, cost
effectiveness of continued letrozole vs. therapeutic substitution (TS)
to generic anastrozole was evaluated separately in cohorts defined on
years of endocrine therapy remaining. TS to generic anastrozole was
assumed to result in an additional 5% of patients discontinuing
endocrine therapy. Probabilities of distant recurrence and death were
taken from reports of BIG 1-98, ATAC, the Early Breast Cancer Trialists'
Collaborative Group meta-analysis of tamoxifen, and other published
sources. Carry-over effects of aromatase inhibitors were assumed to be
proportional to treatment duration. Costs of aromatase inhibitors were
assumed to decline by 75% with generic availability. In treatment-naïve
patients, total expected lifetime costs are $3916 greater with
letrozole vs. anastrozole. However, initiation of treatment with
letrozole results in a gain of 0.15 QALYs. Cost per QALY gained with
letrozole vs. anastrozole is $25,846. In patients already receiving
letrozole, the increase in total expected lifetime costs with continued
letrozole vs. TS to anastrozole is between $4200 and
