Letrozole and boneAromatase inhibitors Adjuvant breast cancer treatment associated with bone loss
Letrozole and bone :
Letrozole has been shown to be superior to tamoxifen in advanced breast cancer, while in early breast cancer, The Breast International (BIG) 1-98 Collaborative Group showed superiority of letrozole over tamoxifen, with a risk reduction very similar to that observed with anastrozole in the ATAC trial.59 Additionally, a study investigating the role of letrozole after standard treatment with 5 years of adjuvant tamoxifen therapy has shown a highly significant improvement in disease-free survival with letrozole.
Letrozole is known to increase bone turnover, and its effects have been investigated in healthy postmenopausal women; after 3 months of letrozole therapy, CTX, a marker of bone resorption, had increased by around 20% (p< 0.005). In the BIG 1-98 study, a 50% excess of fractures was observed with a median follow-up of 30 months (8.6% vs. 5.8%).68 In the MA-17 study, patients were randomised to letrozole or placebo after completing 5 years of adjuvant tamoxifen therapy. More diagnoses of osteoporosis were made in the letrozole group, compared with the placebo group, at 5.8% and 4.5% of patients, respectively (p=0.07), and the fracture rate was also slightly increased.62 Recently, the first data from 226 patients evaluated in the MA-17 bone sub-protocol were presented.
Patients receiving letrozole had a significant decrease in BMD at 24 months at both the lumbar spine (p=0.008) and hip (p=0.044); these results strongly suggest that letrozole has similar effects on bone health to that of anastrozole.
Letrozole and bone :
Letrozole has been shown to be superior to tamoxifen in advanced breast cancer, while in early breast cancer, The Breast International (BIG) 1-98 Collaborative Group showed superiority of letrozole over tamoxifen, with a risk reduction very similar to that observed with anastrozole in the ATAC trial.59 Additionally, a study investigating the role of letrozole after standard treatment with 5 years of adjuvant tamoxifen therapy has shown a highly significant improvement in disease-free survival with letrozole.
Letrozole is known to increase bone turnover, and its effects have been investigated in healthy postmenopausal women; after 3 months of letrozole therapy, CTX, a marker of bone resorption, had increased by around 20% (p< 0.005). In the BIG 1-98 study, a 50% excess of fractures was observed with a median follow-up of 30 months (8.6% vs. 5.8%).68 In the MA-17 study, patients were randomised to letrozole or placebo after completing 5 years of adjuvant tamoxifen therapy. More diagnoses of osteoporosis were made in the letrozole group, compared with the placebo group, at 5.8% and 4.5% of patients, respectively (p=0.07), and the fracture rate was also slightly increased.62 Recently, the first data from 226 patients evaluated in the MA-17 bone sub-protocol were presented.
Patients receiving letrozole had a significant decrease in BMD at 24 months at both the lumbar spine (p=0.008) and hip (p=0.044); these results strongly suggest that letrozole has similar effects on bone health to that of anastrozole.
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