Cost-effectiveness of letrozole versus tamoxifen as initial adjuvant therapy in hormone receptor-positive postmenopausal women with early-stage breast cancer.
BACKGROUND
In Breast International Group (BIG) 1-98, a randomized, double-blind trial comparing 5 years of initial adjuvant therapy with letrozole versus tamoxifen in postmenopausal women with hormone receptor-positive early breast cancer, letrozole significantly improved disease-free survival by 19% and reduced risk of breast cancer recurrence by 28% and distant recurrence by 27%.


METHODS
A Markov model was used to estimate the incremental cost per quality-adjusted life year (QALY) gained with 5 years of initial adjuvant therapy with letrozole versus tamoxifen from a US health care system perspective. Probabilities and costs of breast cancer recurrence and treatment-related adverse events and health-state utilities were based on published results of BIG 1-98 and other published studies. Costs and QALYs were estimated over the lifetime of a cohort of postmenopausal women with hormone receptor-positive early breast cancer, aged 60 years at initiation of therapy. In our base case, we assumed that benefits of letrozole on risk of breast cancer recurrence are maintained for 5 years after therapy discontinuation ("carry-over effect") and examined the effects of this assumption on results in sensitivity analyses.


RESULTS
Under base-case assumptions, letrozole yields an additional 0.409 QALYs versus tamoxifen at an additional cost of $9705, yielding a cost per QALY gained for letrozole versus tamoxifen of $23,743 (95% confidence interval, $14,087-$51,129). Assuming no carry-over effects, letrozole yields 0.264 QALYs at a cost of $10,341, for a cost per QALY gained of $39,098 (95% confidence interval, $23,968- $83,501).


CONCLUSIONS
In postmenopausal women with hormone receptor-positive early breast cancer, initial adjuvant treatment with letrozole is cost-effective from the US health care system perspective.
Delea
Thomas E
TE
Policy Analysis Inc., Brookline, MA 02445, USA. tdelea@pai2.com
Karnon
Jon
J
Sofrygin
Oleg
O
Thomas
Simu K
SK
Papo
Natalie L
NL
Barghout
Victoria
V
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000970:Antineoplastic Agents / Q000191:economics* / Q000627:therapeutic use; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000401:mortality / Q000473:pathology; D017024:Chemotherapy, Adjuvant; D003362:Cost-Benefit Analysis; D016527:Drug Costs; D005260:Female; D006801:Humans; D000077289:Letrozole; D008390:Markov Chains; D008875:Middle Aged; D017059:Models, Econometric; D009376:Neoplasms, Hormone-Dependent / Q000188:drug therapy* / Q000401:mortality / Q000473:pathology; D009570:Nitriles / Q000009:adverse effects / Q000191:economics* / Q000627:therapeutic use; D017698:Postmenopause; D019057:Quality-Adjusted Life Years; D016032:Randomized Controlled Trials as Topic; D013629:Tamoxifen / Q000009:adverse effects / Q000191:economics* / Q000627:therapeutic use; D014230:Triazoles / Q000009:adverse effects / Q000191:economics* / Q000627:therapeutic use
D000970:Antineoplastic Agents; D009570:Nitriles; D014230:Triazoles; D013629:Tamoxifen; D000077289:Letrozole