The Relationship between Prostate Biopsy Results and PSA and Free PSA Ratio Changes in Elevated Serum PSA Patients with and without Antibiotherapy

OBJECTIVES: To evaluate the impact of antibiotic treatment on total prostate specific antigen (PSA) levels and free/total (f/t) PSA ratio and the relevance of these changes to prostate biopsy results. METHODS: We retrospectively evaluated 1,062 patients with elevated age-adjusted serum PSA levels who underwent prostate biopsy between 2004 and 2016. A total of 303 cases with followup PSA levels and f/t PSA ratio before and after antibiotherapy were included into this study. There were 214 patients with persistent elevated serum PSA levels after antibiotic treatment followed by prostate biopsy (treatment group) and 89 patients who had prostate biopsy after a mean followup of 1 month without antibiotherapy (control group). The groups were compared with regard to both 5% and 10% cut off changes in serum PSA levels and f/t PSA ratios. RESULTS: Antibiotic treatment had no impact on the relation between serum PSA levels and biopsy results at both cut off values. On the other hand, f/t PSA ratio changes at both cut off values with relevance to antibiotic treatment were found to be related with histopathologic results. While increase in f/t PSA ratio was more related with benign biopsies, decrease in f/t PSA ratio was more related with cancer (for 5% cut off value p= 0.014, p= 0.004; for 10% cut off value p= 0.026, p= 0.014). CONCLUSION: Changes at f/t PSA ratio rather than total PSA only, particularly in antibiotic treated cases appear to be more useful in decision making for biopsy.