Assessing bone mineral density as a risk factor for early clinically significant prostate cancer

Abstract

4796 Background: This investigation is a prospective study of bone mineral density (BMD) in men with recently diagnosed clinically significant, but non-advanced prostate cancer (CaP). Three hormonal systems that impact on BMD and that may influence CaP growth are estrogens, vitamin D, and insulin-like growth factors. We hypothesize that if estrogen or vitamin D is more dominant, then denser bones will be associated with protection from CaP. Conversely, if the IGF-1 axis is more dominant, then denser bones will be associated with a greater risk for clinically significant CaP. Methods: Patients with newly diagnosed localized CaP with Gleason scores of 6 or greater had their hip BMD assessed by DEXA scan. Cases were compared against the age-, race-, and weight-standardized reference population to compute Z-scores and against 20 - 40 year-old, race-identical men for T-scores. Cases having surgery for cure are also followed prospectively to investigate the prognostic value of baseline BMD for event-free survival. Preliminary Results: Twelve patients have been enrolled in this ongoing study: 7 whites and 5 blacks with a mean age of 61 years and Gleason scores of six (8), seven (2), and nine (2). DEXA scans have been completed for nine. Z-scores have the following distribution: greater than one (3), minus one to one (6). Similarly, T-scores are: greater than 1.5 (3), between minus one to one (5), and less than one (1). None of our subjects have osteoporosis (T-score <2.5). Conclusions: Although preliminary, this suggests that men with clinically significant CaP have elevated BMD at baseline relative to that of an age-, race-, and weight-standardized population (Z-scores). We continue to increase our sample size and also will follow those men who have surgery for cure to see if BMD is associated with biochemical recurrence. No significant financial relationships to disclose.