Introduction Obesity is consistently linked with prostate cancer (PCa) recurrence and mortality although the mechanism is unknown. Impaired glucose regulation, which is common among obese individuals, has been hypothesized as a potential mechanism for PCa tumor growth. In this study we explore the relationship between serum glucose at time of treatment and risk of PCa recurrence following initial therapy. Methods The study group was comprised of 1,734 men treated with radical prostatectomy (RP) or radiation therapy (RT) for localized PCa between 2001–2010. Serum glucose levels closest to date of diagnosis were determined. PCa recurrence was determined based on PSA progression (nadir PSA + 2 for RT; PSA ≥ 0.2 for RP) or secondary therapy. Multivariate Cox regression was performed to determine whether glucose level was associated with BCR after adjusting for age, race, BMI, comorbidity, diagnosis of diabetes, Gleason Sum, PSA, treatment, and treatment year. Results Recurrence was identified in 16% of men over a mean follow-up period 41 months (range 1 – 121 months). Those with elevated glucose (≥ 100 mg/dL) had a 50% increased risk of recurrence (HR 1.5, 95% CI: 1.1–2.0) compared to those with a normal glucose level (< 100 mg/dL). This effect was seen in both those undergoing RP (HR 1.9, 95% CI 1.0–3.6) and those treated with RT (HR 1.4, 95% CI 1.0–2.0). Conclusion Glucose levels at the time of PCa diagnosis are an independent predictor of PCa recurrence for men undergoing treatment for localized disease.

Our results highlight the overutilization of imaging, even in an integrated health care system without financial incentives encouraging provision of health care services. Paradoxically, imaging remains underutilized among high-risk patients who could potentially benefit from it most.