Identification of low oxygen tolerating bacteria in prostate secretions of cancer patients: aetiological and therapeutic relevance

The sun-sensitive microaerophilic organism Propionibacterium acnes shows linkage with prostate cancer. That circumcision reduces risk of this cancer further supports a role for anaerobes since circumcision reduces the number of anaerobes on the glans penis. A 1988 study linked anaerobes with prostate cancer but considered them to be opportunists in a necrotic tumour. Rediscovering this research led us to revisit the previous hypothesis suggesting that decades of a similar process to that linking Helicobacter pylori (also microaerophilic) to stomach cancer might also be relevant in prostate cancer; and justified this feasibility study to seek evidence to support this hypothesis. Two groups of patients were studied: patients with prostate cancer from Barts prostate clinic (active surveillance, n=18) and new referrals with urinary symptoms for investigation through Newham General Hospital (n=21). Urine samples from post-massage examinations were screened with matrix-assisted laser desorption/ionisation time-of-flight (MALDI-TOF) for identification of bacteria grown under anaerobic conditions. Ten preoperative urine samples investigated for non-urological conditions were controls. Anaerobic organisms were identified in eight (41%) of 18 patients in the active surveillance group, nine (43%) of 21 in the new referral group, and none of ten control samples. In a post-hoc analysis, anaerobes were associated with raised prostate-specific antigen (PSA) (1 [9%] of 11 men with PSA