1120 Background: TAS-108, a novel steroidal antiestrogen, has demonstrated a favorable safety profile, including lower agonistic activity on uterus than tamoxifen and supportive effect on bone in preclinical studies. The potential tissue-specific effect of TAS-108 was investigated in postmenopausal breast cancer patients included in a randomized phase II study. (The clinical efficacy and safety results were presented at the 31st San Antonio Breast Cancer Symposium). Methods: Postmenopausal women aged 20–80 years with hormone receptor-positive metastatic breast cancer were eligible for this study and treated with oral TAS-108 (40, 80, or 120 mg/day) once a day. Endometrial thickness (ET) was measured by ultrasonography. The change in Bone Mineral Density (BMD) at lumber spine was assessed by dual energy X-ray absorptiometry. Hormone levels, bone metabolism markers, and serum lipid parameters were also measured at regular intervals. Wilcoxon signed-rank test was used to assess the significance of changes or percentage changes from baseline. Results: Ninety one patients with a median age of 62 years (range 44–80) were included in the analysis population. TAS-108 did not cause significant endometrial thickening (median baseline ET 3.3 mm, last point ET 3.6 mm; n = 36). In particular, after at least 1 year of treatment in 13 cases, no clinically significant increase in ET was found. No change was observed in median BMD (+0.74%; n = 20). Serum carboxy-terminal telopeptide of type I collagen (I CTP) levels remained unchanged although the decrease in osteocalcin levels was significant (p = 0.019; n = 49) in patients without bone metastasis. Median triglyceride levels significantly decreased from 104.0 to 85.0 mg/dl (p = 0.000) after 4 weeks of treatment, while there were no changes in other lipid parameters. An increase in sex hormone-binding globulin and testosterone levels were observed. Conclusions: TAS-108 may have no harmful effects within these parameters and could be used safely. However, further study in a greater number of cases is needed to identify the effect of the long-term use of TAS-108 on the uterus and bone. [Table: see text]
Chemotherapy (CT) and hormonotherapy (HT) as neoadjuvant treatment in luminal breast cancer patients: results from the GEICAM/2006-03, a multicenter, randomized, phase-II study
