Serum levels of insulin-like growth factor-I in operable breast cancer in relation to the main prognostic variables and their perioperative changes in relation to those of prolactin.

AIMS AND
BACKGROUND: In addition to estrogens, prolactin (PRL) and IGF-I have also appeared to stimulate breast cancer growth. The present study was performed to evaluate IGF-I blood levels in operable breast cancer in relation to PRL values and the main prognostic variables.
METHODS: The study included 40 patients, clinical stage T1-3NO-2MO. Venous blood samples were collected before and 7 days after surgery. PRL and IGF-I were measured by radioimmunoassay. The control group consisted of 50 healthy women.
RESULTS: Mean serum levels of IGF-I were significantly higher in patients than in controls, without any apparent relation to the main prognostic variables, including estrogen receptor and node status. Surgery-induced hyperprolactinemia occurred in 22/40 patients. IGF-I mean concentrations observed in the postoperative period in patients with surgery-induced hyperprolactinemia were significantly lower than those seen in patients showing no postoperative PRL rise.
CONCLUSIONS: The study showed that operable breast cancer may be associated with abnormally high levels of tumor growth factor IGF-I, and that surgery was followed by an IGF-I decline only in patients who showed surgery-induced hyperprolactinemia. Our previous studies have shown that postoperative hyperprolactinemia is a favorable prognostic factors for operable breast cancer. The present study, by showing that a postoperative PRL rise is associated with a fall in IGF-I, would suggest that surgery-induced hyperprolactinemia may determine a lower tumor relapse rate by determining a diminished secretion of breast tumor growth factor IGF-I.