Seminars in oncology
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Seminars in oncology · Apr 2006
Randomized Controlled Trial Multicenter StudyPreventing relapse beyond 5 years: the MA.17 extended adjuvant trial.
For patients with hormone-receptor-positive breast cancer, the risk of relapse remains significant even after successfully completing 5 years of adjuvant tamoxifen. The use of tamoxifen beyond 5 years is not recommended, but the need to protect against relapse following tamoxifen is clear. The third-generation aromatase inhibitors offer a new approach to treating postmenopausal women with receptor-positive early stage breast cancer through the potent and specific systemic inhibition of estrogen synthesis. ⋯ Letrozole showed minimal side effects compared with placebo; adverse effects on bone metabolism of uncertain clinical significance were the most noteworthy side effect. Thus, the updated results from the MA.17 trial support the previous findings and show extended adjuvant therapy with letrozole to be a well-tolerated protection against the continuing risk of breast cancer recurrence for thousands of women currently receiving standard adjuvant tamoxifen. The re-randomization of MA.17 patients to an additional 5 years of letrozole or to no treatment will provide further insights into the benefits and side effects of long-term treatment.
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Seminars in oncology · Apr 2006
Randomized Controlled Trial Multicenter StudyThe use of early adjuvant aromatase inhibitor therapy: contributions from the BIG 1-98 letrozole trial.
Letrozole has proven efficacious in a variety of therapeutic scenarios, including that of extended adjuvant therapy following 5 years of tamoxifen treatment in postmenopausal women with estrogen-receptor-positive early breast cancer. The Breast International Group 1-98 trial (BIG 1-98) is the first to study the efficacy of upfront letrozole treatment and the first to evaluate the benefits of initial versus sequential aromatase inhibitor therapy. At 25.8 months of follow-up, the primary core analysis of BIG 1-98 compared the efficacy of upfront letrozole treatment with that of upfront tamoxifen treatment in 8,010 postmenopausal women with early breast cancer. ⋯ Letrozole has an efficacy advantage over tamoxifen and can now be considered part of standard adjuvant therapy for postmenopausal women with endocrine-responsive breast cancer. Women at increased risk for recurrence may obtain protective benefit from letrozole. Letrozole is generally well tolerated and is associated with a similar frequency of serious side effects, but fewer deaths, than tamoxifen.