to those taking AIs, especially those who started on tamoxifen, switched AIs, or d/cd

[Lani]

AIs and went on tamoxifen

1)there seems to be more effect on bone the longer you are on AIs

2)there seems to be no difference between femara and arimidex (letrozole and anastrozole )

3)it seems to be better for your bones to have started on an AI then to have started on an tamoxifen and have switched to an AI

4)There seems to be more benefit for your bones to switch to tamoxifen after being on an AI

these judgements/conclusions were made by the researches based on biomarkers of bone turnover, not xrays or history of fracture it seems--will read further...

Breast Cancer Res Treat. 2009 Nov 26. [Epub ahead of print]
A study of the effects of the aromatase inhibitors anastrozole and letrozole on bone metabolism in postmenopausal women with estrogen receptor-positive breast cancer.
McCaig FM, Renshaw L, Williams L, Young O, Murray J, Macaskill EJ, McHugh M, Hannon R, Dixon JM.

Breakthrough Research Unit, Edinburgh Breast Unit, Western General Hospital, Edinburgh, EH4 2XU, Scotland, UK.
ALIQUOT (Anastrozole vs. Letrozole, an Investigation of Quality Of Life and Tolerability) was a prospective, open-label, randomized pharmacodynamic study designed to assess the effects of aromatase inhibitors (AIs) on bone turnover in healthy postmenopausal women with estrogen receptor-positive breast cancer. Ninety-four patients were randomized to receive either 12 weeks of letrozole (2.5 mg; n = 42) followed by 12 weeks of anastrozole (1 mg), or 12 weeks of anastrozole (1 mg; n = 42) followed by 12 weeks of letrozole (2.5 mg). After completion of the study period, patients in the immediate adjuvant group were either switched to tamoxifen (n = 38) or continued on anastrozole or letrozole. In the beginning of the study, 42 patients had taken tamoxifen within 3 months. Patients taking drugs likely to affect bone metabolism, including bisphosphonates, were excluded. Eighty-four patients had complete sample measurements and were included in the analysis. Prior tamoxifen therapy resulted in a significantly lower mean baseline procollagen type 1 N-terminal propeptide (PINP) compared with patients with no prior tamoxifen. There were no significant differences in bone markers between AIs at any time. By 6 months, significant increases were seen in PINP, C-terminal telopeptides (CTX), bone specific alkaline phosphatise (ALP), and urinary N-terminal telopeptides (NTX). Patients with prior tamoxifen had significantly greater increases than patients with no prior tamoxifen. Patients treated with 3 months of tamoxifen following 6 months of an AI showed a significant decrease in markers of bone resorption, serum CTX and urinary NTX. In conclusion, AI-induced bone turnover increases over time. Anastrozole and letrozole produce similar effects on bone metabolism and turnover. Stopping tamoxifen therapy and starting AIs results in a significantly greater increase in bone turnover compared with commencing AIs in tamoxifen-naïve patients. Patients given tamoxifen following AI therapy showed a decrease in markers of bone resorption.

PMID: 19941160 [PubMed - as supplied by publisher]