Background: Some, but not all, published results have shown an
association between circulating blood levels of some insulin-like
growth factors (IGFs) and their binding proteins (IGFBPs) and the
subsequent risk for prostate cancer.
Purpose: To assess the association between levels of IGFs and
IGFBPs and the subsequent risk for prostate cancer.
Data Sources: Studies identified in PubMed, Web of Science, and
Study Selection: The principal investigators of all studies that published
data on circulating concentrations of sex steroids, IGFs, or
IGFBPs and prostate cancer risk using prospectively collected blood
samples were invited to collaborate.
Data Extraction: Investigators provided individual participant data
on circulating concentrations of IGF-I, IGF-II, IGFBP-II, and IGFBPIII
and participant characteristics to a central data set in Oxford,
Data Synthesis: The study included data on 3700 men with prostate
cancer and 5200 control participants. On average, case patients
were 61.5 years of age at blood collection and received a
diagnosis of prostate cancer 5 years after blood collection. The
greater the serum IGF-I concentration, the greater the subsequent
risk for prostate cancer (odds ratio [OR] in the highest vs. lowest
quintile, 1.38 [95% CI, 1.19 to 1.60]; P 0.001 for trend). Neither
IGF-II nor IGFBP-II concentrations were associated with prostate
cancer risk, but statistical power was limited. Insulin-like growth
factor I and IGFBP-III were correlated (r 0.58), and although
IGFBP-III concentration seemed to be associated with prostate cancer
risk, this was secondary to its association with IGF-I levels.
Insulin-like growth factor I concentrations seemed to be more positively
associated with low-grade than high-grade disease; otherwise,
the association between IGFs and IGFBPs and prostate cancer
risk had no statistically significant heterogeneity related to stage or
grade of disease, time between blood collection and diagnosis, age
and year of diagnosis, prostate-specific antigen level at recruitment,
body mass index, smoking, or alcohol intake.
Limitations: Insulin-like growth factor concentrations were measured
in only 1 sample for each participant, and the laboratory
methods to measure IGFs differed in each study. Not all patients
had disease stage or grade information, and the diagnosis of prostate
cancer may differ among the studies.
Conclusion: High circulating IGF-I concentrations are associated
with a moderately increased risk for prostate cancer.
|Translated title of the contribution||Insulin-like growth factors, their binding proteins, and prostate cancer risk: Analylsis of individual patient data from 12 prospective studies|
|Pages (from-to)||461 - 471|
|Number of pages||11|
|Journal||Annals of Internal Medicine|
|Publication status||Published - Oct 2008|