Effect of leuprolide on serum amyloid-β peptide levels and memory in patients with prostate cancer with biochemical recurrence

Objective: To investigate whether prostate cancer patients receiving leuprolide demonstrated objective cognitive decline accompanied by a change in plasma levels of amyloid-β. Methods: Between November 19, 2003, and July 21, 2008, we prospectively enrolled 50 patients with biochemical recurrence of prostate cancer and measured plasma amyloid-β peptide 40 and amyloid-β peptide 42 levels with sandwich enzyme-linked immunosorbent assay at baseline before the first leuprolide injection and at 2, 4, and 12 months. The Mini-Mental State Examination was used to assess 49 patients at baseline and at subsequent visits, and 24 were also assessed by the California Verbal Learning Test-Short Form. Results: Patients were a median age of 71 years (range, 59-89 years). Compared with baseline levels, plasma amyloid-β peptide 40 levels were increased at 2 months (P =.04) and 4 months (P =.02). Age was correlated with plasma amyloid-β peptide 40 levels (P =.003) and likely accounted for this relationship. Plasma amyloid-β peptide 42 and performance on cognitive tasks did not differ from baseline, but memory measures improved slightly after baseline, most likely due to a practice effect. Conclusion: Leuprolide therapy was not associated with a decline in cognition or memory function or with elevated plasma amyloid short-term. Larger studies are needed to confirm these findings.