EFFECTS OF AROMATASE COMPLEX SELECTIVE-INHIBITION ON INSULIN-LIKE-GROWTH-FACTOR-1 AND INSULIN-LIKE-GROWTH-FACTOR BINDING-PROTEIN-3 CIRCULATING LEVELS IN BREAST-CANCER

The aim of our study is to evaluate insulin-like growth factor (IGF) a nd IGF binding protein (IGFBP)-3 circulating levels in postmenopausal women treated with type I aromatase inhibitor formestane for breast ca ncer. Sixty-three patients at their first relapse entered the trial an d were randomly given formestane at 250 mg or 500 mg i.m. fortnightly. Effects of the endocrine treatment on IGF-1 and IGFBP-3 were measured before and during therapy at scheduled times. IGF-1 and IGFBP-3 seems to slightly increase in both the dose groups, but only IGFBP-3 levels showed statistically significant fluctuation (baseline vs 4 weeks, p= 0.01925; baseline vs 10 weeks, p=0.04537). These modifications are unl ikely to be related to clinical status because they were observed both in responsive and unresponsive patients. This report demonstrates tha t hormonal treatments for breast cancer (particularly, aromatase inhib itor administration) can modify growth factor disposition to tumour.