Biomarkers of glucose homeostasis and inflammation with risk of prostate cancer: A case-cohort study
Menée à l'aide d'échantillons sanguins collectés auprès de 1 303 témoins et 703 patients atteints d'un cancer de la prostate, cette étude analyse l'association entre une hyperglycémie (évaluée par les taux d'hémoglobine A1c, du peptide C et de la protéine C réactive) et le risque de développer la maladie, en fonction du stade et du grade de la tumeur
Background: Few prospective studies have examined biomarkers of glucose homeostasis or inflammation with prostate cancer risk by tumor stage or grade. Methods: We conducted a case-cohort study to examine associations of pre-diagnosis hemoglobin A1c (HbA1c), c-peptide, and c-reactive protein (CRP) with prostate cancer risk overall and stratified by tumor stage and grade. The study included 390 non-aggressive (T1-2, N0, M0 and Gleason score <8) and 313 aggressive cases (T3-4, or N1, or M1, or Gleason score 8-10) diagnosed after blood draw (1998-2001) and up to 2013, and a random sub-cohort of 1,303 cancer-free men at blood draw in the Cancer Prevention Study-II Nutrition Cohort. Prentice-weighted Cox proportional hazards regression models were used to estimate hazards ratios (HRs) and 95% confidence intervals (CIs). Results: In the multivariable-adjusted model without body mass index (BMI), HbA1c was inversely associated with non-aggressive prostate cancer (HR per unit increase: 0.89, 95% CI: 0.80-1.00, P=0.04). Analyses stratified by tumor stage and grade separately showed that HbA1c was inversely associated with low-grade prostate cancer (HR per unit increase: 0.89, 95% CI: 0.80-1.00) and positively associated with high-grade prostate cancer (HR per unit increase: 1.15, 95% CI: 1.01-1.30). C-peptide and CRP were not associated with prostate cancer overall or by stage or grade. Conclusions: The present study suggests that associations of hyperglycemia with prostate cancer may differ by tumor grade and stage. Impact: Future studies need to examine prostate cancer by tumor stage and grade, and to better understand the role of hyperglycemia in prostate cancer progression.