BERKELEY, CA (UroToday.com) - This study is extremely practical and adds some information concerning the role of elevated PSA and the diagnosis of prostate cancer. Non-malignant conditions such as benign prostate hyperplasia and inflammation are known factors that can raise PSA levels overlapping the range of suspicion for cancer. Although controversial, antibiotics are often prescribed for men with newly increased PSA on the presumption that the patient has subclinical infectious prostatitis.⁽¹⁾ Some studies have suggested that the use of antibiotics in patients with elevated PSA can reduce the levels of PSA and the biopsy could be avoided in up to half of patients.^(2-4)

The authors conducted a randomized, placebo controlled, prospective study to evaluate the effect of antibiotics in 98 patients with proven type IV prostatitis and increased PSA. The diagnosis of type IV prostatitis was made by a modified Mears-Stamey test and participants were randomized to placebo or ciprofloxacin for 4 weeks. All underwent ultrasound and 12-core prostate biopsy, independently of final PSA value, a methodological strength.

Around 50% of patients diagnosed with prostatitis type IV presented elevated PSA, and antimicrobial therapy was no more effective than placebo in reducing PSA. Furthermore, the proportion of patients with cancer was similar in both groups. Of all patients studied, 50% showed a decrease in PSA irrespective of the treatment, and 30% of individuals in whom the PSA fell also had a diagnosis of cancer demonstrated on biopsy of the prostate. The decrease in PSA after antibiotic therapy did not eliminate the need for biopsy.

The main limitation of this study is the small sample for definitive conclusions. The patients included in the study may not have represented a random sample of male patients because only those with type IV prostatitis were included. The data consistently indicates that the use of drugs with intent to prevent a prostate biopsy should be considered carefully. Unfortunately, there was no information in the literature whether patients who received antibiotics and had a reduction in PSA and a subsequent diagnosis of cancer presented with disease more or less aggressive in its evolution.

A previous study evaluated the effects of antibiotics on serum PSA in men with PSA between 4 and 10 ng/ml (and normal digital rectal examination) and the incidence of prostate cancer by performing prostate biopsies in all patients regardless of post-treatment PSA.⁽⁵⁾ Although antibiotic therapy decreases serum PSA, it does not decrease the risk of prostate cancer even if the PSA levels drop to below 4 ng/ml.

The valuable pioneering information in the present study is that PSA behavior (kinetics) does not differ in patients using antibiotics or placebo and, surprisingly, it is not related to the presence or absence of cancer, although it decreases to low and normal levels (less than 2.5 ng/ml).

References:

1. Dirim A, Tekin MI, Koyluoglu E, Oguzulgen AI, Peskircioglu L, Ozkardes H. Do changes in a high serum prostate-specific antigen level and the free/total prostate-specific antigen ratio after antibiotic treatment rule out biopsy and the suspicion of cancer? Urol Int. 2009;82(3):266-9.
2. Bozeman CB, Carver BS, Eastham JA, Venable DD. Treatment of chronic prostatitis lowers serum prostate specific antigen. J Urol. 2002 Apr;167(4):1723-6.
3. Guercio S, Terrone C, Tarabuzzi R, Poggio M, Cracco C, Bollito E, et al. PSA decrease after levofloxacin therapy in patients with histological prostatitis. Arch Ital Urol Androl. 2004 Dec;76(4):154-8.
4. Serretta V, Catanese A, Daricello G, Liotta R, Allegro R, Martorana A, et al. PSA reduction (after antibiotics) permits to avoid or postpone prostate biopsy in selected patients. Prostate Cancer Prostatic Dis. 2008;11(2):148-52.
5. Baltaci S, Suer E, Haliloglu AH, Gokce MI, Elhan AH, Beduk Y. Effectiveness of antibiotics given to asymptomatic men for an increased prostate specific antigen. J Urol. 2009 Jan;181(1):128-32.