Serum insulin-like growth factor-I and insulin-like growth factor binding protein-3 following chemotherapy for advanced breast cancer.
BACKGROUND
Insulin-like growth factor-I (IGF-I) and IGF binding protein-3 (IGFBP-3) appear to influence the growth of breast cancer cells in vitro, and epidemiological studies suggest higher serum IGF-I levels increase the risk of breast cancer. IGF-I and IGFBP-3 have therefore been measured in women with advanced breast cancer to determine if changes in serum levels predict the response to treatment by chemotherapy.


METHODS
Serum IGF-I and IGFBP-3 levels were measured in 14 patients before and after 1 week of chemotherapy. Changes in serum levels were compared with duration of survival.


RESULTS
Mean basal serum levels of IGF-I and IGFBP-3 were not significantly different between patients with advanced breast cancer and controls or women with early breast cancer. Serum IGFBP-3 fell significantly 1 week after initiation of chemotherapy. Patient survival was not significantly related to baseline IGF-I or IGFBP-3 levels, but when the fall in serum levels 1 week after starting treatment was expressed either as absolute change or as a percentage of baseline, those individuals with a decrease in IGFBP-3 greater than the median had significantly poorer survival (median survival 5.5 months vs 18 months). These results were independent of other prognostic variables such as previous disease-free survival, and were also unaffected by the change in serum albumin with treatment. The fall in IGF-I and IGFBP-3 with chemotherapy mainly occurred in those with hepatic metastases, but prediction of survival was explained solely by the extent of the fall in IGFBP-3.


CONCLUSIONS
This preliminary study has shown that serum IGFBP-3 falls significantly following initiation of chemotherapy and the extent of reduction significantly predicts the response to treatment.
Holdaway
Ian M
IM
Departments of Endocrinology and Oncology, Auckland Hospital, Auckland, New Zealand. ian@adhb.govt.nz
Mason
Barbara H
BH
Lethaby
Anne E
AE
Singh
Vijay
V
Harvey
Vernon J
VJ
Thompson
Paul I
PI
Evans
Barrie D
BD
D000328:Adult; D000368:Aged; D000970:Antineoplastic Agents / Q000627:therapeutic use; D001943:Breast Neoplasms / Q000188:drug therapy / Q000473:pathology / Q000503:physiopathology*; D005260:Female; D006801:Humans; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000097:blood / Q000502:physiology*; D007334:Insulin-Like Growth Factor I / Q000032:analysis / Q000502:physiology*; D008113:Liver Neoplasms / Q000503:physiopathology* / Q000556:secondary; D008875:Middle Aged; D009367:Neoplasm Staging; D011237:Predictive Value of Tests; D011379:Prognosis; D016019:Survival Analysis
D000970:Antineoplastic Agents; D018972:Insulin-Like Growth Factor Binding Protein 3; D007334:Insulin-Like Growth Factor I