EFFECT OF 2 4-HYDROXYANDROSTENEDIONE DOSES ON SERUM INSULIN-LIKE GROWTH-FACTOR-I LEVELS IN ADVANCED BREAST-CANCER

A number of endocrine treatments for advanced breast cancer seem to af fect serum insulin-like growth factor I (IGF-I). The aim of our study was to investigate IGF-I levels in 33 postmenopausal patients with met astatic disease receiving the selective aromatase inhibitor 4-hydroxya ndrostenedione: 250 mg (16 patients) or 500 mg (17 patients) i.m. fort nightly. Blood samples were collected before, and at one month and 3 m onths after the beginning of treatment for radioimmunoassay determinat ions. The median patient age was 56 and 60 years in the 250 and 500 mg groups respectively. Most patients had a disease free interval greate r than or equal to 2 years and were oestrogen receptor positive. Objec tive responses were obtained in 3 patients (complete response, 1) in t he 250 mg group, and in 7 patients (complete response, 3) in the 500 m g group. No significant IGF-I variations were seen in the 250 mg group , whereas a significant increase after 3 months (181.57 +/- 84.78 ng/m l versus 272.47 +/- 213.22 ng/ml, p = 0.0032) was observed in the 500 mg group. No IGF-I variations were seen between responsive and unrespo nsive patients in either treatment group. Our results in the 500 mg gr oup are close to those obtained with aminoglutethimide and seem to agr ee with the hypothesis of an oestrogen-induced suppression of IGF-I ci rculating levels.