A Multi-Center Study of the Effects of Toremifene (tor) and Anastrozole (ana) on Serum Lipids and Bone Metabolism in Postmenopausal Patients with Estrogen Receptor (er) Positive Breast Cancer: Interim Report.

645 Background: We have already reported the data that the antiestrogen TOR has better effects than tamoxifen on serum lipid metabolism (ASCO 2003, Breast Cancer Res. Treat 2004). In this study, we evaluated the time course effects of TOR and ANA on serum lipids profile and bone metabolism in ER positive, postmenopausal breast cancer patients with adjuvant hormone therapy. This is the first study to compare TOR and ANA. Methods: Patients were randomly allocated to a TOR40mg/day group (36 cases) or an ANA1mg/day group (33 cases). Serum lipids were measured at before, and 6 and 12 months after the initiation of administration. Changes in the serum lipids and bone markers were compared. Results: Results of lipids: In the TOR group, total cholesterol (TC), LDL, ApoB and Triglyceride (TG) significantly decreased at 6 and/or 12 months compared with the values before the start of administration (p<0.05). HDL and ApoA1 significantly increased at 6 and 12 months in the TOR group (p<0.0002), but ApoA1 at 12 months also significantly increased in the ANA group (p=0.02). Between the TOR and ANA groups, the changes in the percentage of the values of TC, HDL, LDL, ApoA1 and ApoB were significantly different at 6 and/or 12 months (p<0.05). Results of bone markers: BAP significantly increased in the ANA group (p<0.0001); in contrast, NTx significantly decreased in the TOR group (p<0.0001). Between the TOR and ANA groups, the changes in the percentage of the values of BAP and NTx were significantly different at 6 and 12 months (p<0.005). Conclusions: TOR and ANA have different profiles. These findings indicate that TOR has beneficial effects on both lipids and bone metabolism in postmenopausal patients with breast cancer. No significant financial relationships to disclose.