With numerous factors capable of influencing prostate specific antigen (PSA) levels and therefore the likelihood of biopsy, this multi-centred randomised controlled trial (RCT) was designed to see if two weeks of ciprofloxacin compared to placebo would significantly reduce PSA levels so that biopsy could be avoided. All men with a normal rectal examination and a PSA >2.5ng/ml, were invited to take part, once exclusion criteria had been checked. These included previous biopsies (whether positive or not), recent infection or antibiotic use, five-alpha reductase inhibitor (5ARI) use and allergy to antibiotics. The PSA was repeated between 21 and 45 days from initial and just prior to transrectal 12-core biopsy. Seventy-seven men with a mean age of 61 took part, with 47% having a positive biopsy (59% in the placebo arm, 34% in the antibiotic arm, p=0.04). The PSA rose in 19/36, was static in one man and fell in 16/40, but cancer detection was not significantly different between the PSA responses. The biopsy result was also not predicted by the PSA change and one patient in the antibiotic arm developed sepsis due to a ciprofloxacin resistant organism. Only five men (four in the control group, one in the antibiotic group) had a repeat PSA below 2.5 (and therefore could have avoided a biopsy) but two had positive cores. Due to poor recruitment and an interim analysis suggesting the null hypothesis to be likely, the trial was stopped early. The numbers may have been too small to produce a meaningful result, especially the cancer detection rate between the groups. There was no standardisation of the time to biopsy and the authors hypothesised that the antibiotic course may have been too short and the time to biopsy too brief. However, this is the first randomised trial in asymptomatic men to show no benefit from using antibiotics to normalise PSA and avoid a biopsy. Whilst the hope of avoiding biopsy has to be welcomed, the risk of further waits, side-effects, resistance promotion and possibly increased post-biopsy sepsis coupled with these results make repeated PSA tests in the hope that they will normalise, relatively futile. However, future studies would help confirm this.
