Blood glucose, glucose balance, and disease-specific survival after prostate cancer diagnosis in the Finnish Randomized Study of Screening for Prostate Cancer.

Introduction: Diabetes mellitus has been linked with adverse prostate cancer (PCa) outcomes. However, role of hyperglycemia in PCa progression is unclear. We evaluated the link between hyperglycemia and PCa survival among Finnish PCa patients.

Methods: The study cohort included 1770 men with data on fasting glucose and diagnosed with PCa within the Finnish Randomized Study of Screening for PCa in 1995-2009. Additionally, 1398 men had data on glycated hemoglobin (HbA1c). Information on fasting glucose and HbA1c measurements was obtained from the regional laboratory database. Antidiabetic medication use was obtained from the prescription database of the Social Insurance Institution (SII). Time-dependent Cox regression analysis was used to estimate hazard ratios (HRs) and 95% confidence intervals for PCa death among diabetic, impaired glucose tolerant, and normoglycemic men.

Results: During median follow-up of 9.9 years after the diagnosis, 182 men died from PCa. After adjustment for tumor stage, Gleason grade, and PSA level at diagnosis, diabetic fasting glucose level after PCa diagnosis was associated with elevated risk of PCa death compared to normoglycemic men (HR 1.67 95% CI 1.18-2.36). The risk association was strongest among participants with localized cancer at diagnosis; HR 2.39, 95% CI 1.45-3.93. The risk elevation was observed for glucose measurements taken up to 5 years earlier. Diabetic glucose levels measured before the diagnosis were not associated with PCa death.

Conclusion: Our study cohort suggests an increased risk of PCa death in men with diabetic fasting blood glucose levels, supporting the role of hyperglycemia as a risk factor for PCa progression.