Prostatitis as a risk factor for prostate cancer.
BACKGROUND: The association of infection or inflammation of the prostate with prostate cancer has been suggested but not established. This study was undertaken to investigate this association. METHODS: Cases were Olmsted County, Minnesota, residents with histologically proven prostate cancer diagnosed between January 1980 and December 1996. Cases (n = 409) were each matched to 2 control subjects (n = 803) on age at diagnosis of prostate cancer, residency in Olmsted County, and duration of the community medical record. The medical record of each subject was reviewed for a history of acute or chronic bacterial prostatitis or chronic pelvic pain syndrome (inflammatory type). RESULTS: The relative odds of prostate cancer were elevated in men with history of any type of prostatitis (odds ratio [OR] = 1.7; 95% confidence interval [CI] = 1.1-2.6) or acute prostatitis (2.5; 1.3-4.7). The mean time from most recent episode of acute prostatitis to the diagnosis of prostate cancer was 12.2 years. After exclusion of men with acute prostatitis 2 years before the index date, the relationship was somewhat reduced (1.9; 0.9-3.8). Chronic bacterial prostatitis was more weakly associated with prostate cancer (1.6; 0.8-3.1), whereas chronic pelvic pain syndrome was not associated at all (0.9; 0.4-1.8). CONCLUSIONS: Infection in the form of acute or chronic bacterial prostatitis may be associated with prostate cancer. However, our data do not provide compelling evidence to support this. As a result of the limitations of current methods of assessing chronic prostatitis, biochemical or tissue markers of infection or inflammation of the prostate may help clarify their role in the pathogenesis of prostate cancer.