STD confirmed to be associated with increased risk of prostate cancer

Researchers confirmed previous findings that the sexual transmitted infection known as Trichomonas vaginalis is associated with an increased risk of prostate cancer in a study published online September 9 in the Journal of the National Cancer Institute.

Jennifer Rider Stark, ScD, of the department of epidemiology at the Harvard School of Public Health in Boston, and colleagues conducted a case-control study nested within the Physicians' Health Study that included 673 case subjects with prostate cancer and 673 individually matched control subjects. Plasma was assayed for antibodies against T. vaginalis. The relationship of incident prostate cancer, extraprostatic prostate cancer, and cancer predicted to progress to bony metastases or prostate cancer–specific death was investigated.

Although not statistically significant, the size of the association between T. vaginalis–seropositive status and overall prostate cancer risk was similar to that reported previously. A seropositive status was associated with statistically significantly increased risks of extraprostatic prostate cancer and cancer that is likely to progress to bony metastases or prostate cancer–specific death.

"If our findings are confirmed, T. vaginalis could serve as a marker for adverse outcomes in patients for prostate cancer or, more optimistically as a target for secondary chemoprevention," the authors write.

In an accompanying editorial, Peter C. Albertsen, M.D., of the University of Connecticut Health Center, in Farmington, Conn., said that this study is another example of assessing a specific variable to determine the risk of prostate cancer that deserves serious attention.

"Unfortunately, an unintended consequence of prostate-antigen testing is the large number of men diagnosed with incidental disease that now confounds our ability to identify potential causes of clinically significant disease," writes the editorialist, who also pointed out that a much larger study would be required to detect a statistically significant difference between seropositivity and overall prostate cancer risk.