Extended adjuvant treatment with letrozole in breast cancer after 5 years of tamoxifen therapy

PICHON-RIVIERE A,; AUGUSTOVSKI, F; ALCARAZ A; BARDACH, ARIEL; GARCIA MARTÍ, SEBASTIAN; LOPEZ, A; GLUJOVSKY, D; REGUEIRO, A

Documentos de Evaluación de Tecnologías Sanitarias

IECS

Año: 2005 p. 1 - 30

1668-2793

This report is intended to review extended adjuvant treatment with letrozole in breast cancer after 5 years of tamoxifen therapy.7 non systematic revisions, 3 controlled clinical trials, 2 cost-effectiveness studies and documents stating the FDA and the American Society of Clinical Oncology's point of view were identified, Treatment with letrozole significantly improved disease-free survival in a double-blind, multicenter, placebo-controlled concomitant radiochemotherapy (CRCT), the MA-17, which included postmenopausal women with positive hormone receptors who had received five years of tamoxifen in early breast cancer. After a mean follow-up of 2.4 years, the disease-free survival rate for letrozole and placebo were 93% and 87%, respectively. The relative risk for local or metastasic recurrence or for a new contralateral neoplasia in the letrozole group as compared to the placebo group was 0.57 (CI 95%) 0.43-0.75; p<0.001. The global benefit is 43% risk reduction for recurrence or new contralateral cancer being this an absolute risk difference of 2.2% vs placebo at less than three years follow-up. The American Society of Oncology recommends that postmenopausal women completing 5 year tamoxifen therapy with early hormone-sensitive breast cancer should be considered for letrozole therapy. A minimum of 2.5 year treatment is recommended. Adverse and limiting effects of its use: Adverse effects are uncommon, <1%. Flushing, arthralgia, myalgia and arthritis. In general, the adverse effect profile is similar to that of tamoxifen. Less vaginal bleeding was reported. In addition, an increase in new diagnoses of osteoporosis was evidenced.The cost of the medication for one month is 520 to 760 pesos argentinos ($Arg 2005). It would be necessary to place 45 women under treatment for 2.4 years (or 109 women for 1 year) so as to prevent 1 episode of recurrence or new contralateral cancer.