Serum insulin-like growth factor (IGF)-I and IGF-binding protein-3 concentrations and prostate cancer risk: results from the European Prospective Investigation into Cancer and Nutrition.
Allen NE., Key TJ., Appleby PN., Travis RC., Roddam AW., Rinaldi S., Egevad L., Rohrmann S., Linseisen J., Pischon T., Boeing H., Johnsen NF., Tjønneland A., Grønbaek H., Overvad K., Kiemeney L., Bueno-de-Mesquita HB., Bingham S., Khaw KT., Tumino R., Berrino F., Mattiello A., Sacerdote C., Palli D., Quirós JR., Ardanaz E., Navarro C., Larrañaga N., Gonzalez C., Sanchez MJ., Trichopoulou A., Travezea C., Trichopoulos D., Jenab M., Ferrari P., Riboli E., Kaaks R.
BACKGROUND: Some studies suggest that elevated serum insulin-like growth factor (IGF)-I concentrations are associated with an increased risk of prostate cancer and, in particular, with an increased risk of advanced-stage prostate cancer. METHODS: We analyzed the association between prediagnostic serum concentrations of IGF-I and IGF-binding protein-3 (IGFBP-3) and prostate cancer risk in a case-control study nested in the European Prospective Investigation into Cancer and Nutrition. This study includes 630 incident prostate cancer cases and 630 matched control subjects. Odds ratios and their 95% confidence intervals (95% CI) were calculated for prostate cancer risk associated with increasing IGF-I and IGFBP-3 concentrations using conditional logistic regression. RESULTS: The risk of total prostate cancer in the highest versus the lowest third of serum peptide concentration was 1.35 (95% CI, 0.99-1.82; Ptrend = 0.08) for IGF-I, 1.39 (95% CI, 1.02-1.89; Ptrend = 0.12) for the IGF-I residuals after adjusting for IGFBP-3, 1.22 (95% CI, 0.92-1.64; Ptrend = 0.38) for IGFBP-3, and 1.01 (95% CI, 0.74-1.37; Ptrend = 0.75) for the IGFBP-3 residuals after adjusting for IGF-I. There was no significant difference in the association of peptide hormones and prostate cancer by stage of disease, although the association of serum IGF-I concentration with risk was slightly stronger for advanced-stage disease; the odds ratio for the highest versus the lowest third was 1.65 (95% CI, 0.88-3.08; Ptrend = 0.21) for IGF-I and 1.76 (95% CI, 0.92-3.40; Ptrend = 0.11) for IGF-I adjusted for IGFBP-3. CONCLUSIONS: In this large nested case-control study, serum IGF-I concentration is not strongly associated with prostate cancer risk, although the results are compatible with a small increase in risk, particularly for advanced-stage disease; no association for IGFBP-3 was observed.