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Erschienen in:
01.01.2013 | Original paper
Insulin-like growth factors (IGFs) and IGF-binding proteins in active monitoring of localized prostate cancer: a population-based observational study
Erschienen in: Cancer Causes & Control | Ausgabe 1/2013
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Purpose
Active monitoring of prostate cancer requires the selection of low-risk cancers and subsequent identification of disease progression. Our objective was to determine whether serum insulin-like growth factor (IGF)-I, IGF-II, IGF-binding protein (IGFBP)-2 or IGFBP-3 at diagnosis (potential biomarkers of prognosis), and repeated measures of IGFBP-2 (potential biomarker of tumour growth), were associated with annual change in PSA and PSA doubling time (PSADT), proxies for disease progression.
Methods
We investigated associations of circulating IGFs and IGFBPs with PSA measures using multilevel models, in 909 men (recruited between 1999 and 2009) with PSA-detected clinically localized prostate cancer undergoing active monitoring in the United Kingdom. Each man had an average of 14 measurements of PSA during a mean of 4-year follow-up.
Results
IGF-I, IGF-II, IGFBP-2, and IGFBP-3 were not associated with baseline PSA. There was weak evidence that IGF-I at diagnosis was positively associated with a rapid post-diagnosis PSADT (≤4 years vs. >4 years): OR 1.34 (95 % CI 0.98, 1.81) per SD increase in IGF-I. IGFBP-2 increased by 2.1 % (95 % CI 1.4, 2.8) per year between 50 and 70 years, with no association between serial IGFBP-2 levels and PSADT. There was no evidence that serum IGF-II, IGFBP-2, or IGFBP-3, or post-diagnosis IGFBP-2, were associated with PSA kinetics in men with PSA-detected localized prostate cancer.
Conclusions
The weak association of IGF-I with PSADT requires replication in larger datasets, and more definitive evidence will be provided on the maturity of long-term active monitoring cohorts with relevant clinical outcomes (metastasis and prostate cancer mortality).