Sexually Transmitted Disease Linked To Aggressive Prostate Cancer

Men who’ve had a common sexually transmitted disease could, if they go on to develop prostate cancer, run the risk of a more aggressive form of the disease, according to new research. However, trichomoniasis is just one factor among many, as lots of men get this infection without developing more severe prostate cancer.

What do we know already?

Trichomoniasis, sometimes called trich, is a sexually transmitted disease. It’s caused by a single-celled parasite called Trichomonas vaginalis. Around 3 percent of young men carry this infection, although more than half of them will never get any symptoms. When symptoms do occur they’re often mild, such as slight irritation or discharge. The infection can clear up on its own, so you may never know you had it. A 2006 study found a slight link between trichomoniasis in men and a higher risk of getting prostate cancer. One theory is that inflamed tissue is more vulnerable to cancer, and infections could be a cause of inflammation. In a new study, researchers looked at 673 men with prostate cancer and compared them with the same number of healthy men. The average age was 68. All the men had blood samples taken, which were tested for antibodies to trichomoniasis, to find out who’d been infected in the past. The researchers wanted to see if men with prostate cancer were more likely to have had the infection.

What does the new study say?

The new study doesn’t entirely agree with previous research. It found no link between trichomoniasis and developing prostate cancer in the future. However, men with prostate cancer who’d been infected with trichomoniasis did seem more likely to get an aggressive form of cancer that spread outside the prostate gland. Of men with prostate cancer who hadn’t been infected with trichomoniasis, 14 percent had cancer that spread outside their prostate. Of men who’d had the infection, 21 percent had cancer that spread.

How reliable are the findings?

It might be that trichomoniasis leads to a higher risk of aggressive prostate cancer, but it’s difficult to be sure. Finding two things at once doesn’t necessarily mean that one caused the other.

Where does the study come from?

The study was done in the US, with two of the researchers based at Harvard. It appeared in the Journal of the National Cancer Institute, published by Oxford University Press. Funding came from several sources, including the National Cancer Institute and the Harvard University Milton Fund.

What does this mean for me?

It’s possible that trichomoniasis could slightly increase the risk of more severe prostate cancer, but if so, it’s likely to be one factor among many. Of all the men with more serious prostate cancer, only a third had antibodies showing they’d had trichomoniasis, so it obviously doesn’t lead to aggressive cancer in all cases. For most people, trichomoniasis isn’t serious, and can be treated with a short course of a drug called metronidazole; often just one dose.

What should I do now?

For advice about preventing or treating sexually transmitted infections, talk to your GP or visit a genitourinary medicine (GUM) clinic. You can find a clinic near you by visiting http://www.condomessentialwear.co.uk or by calling the NHS sexual health helpline on 0800 567 123. If you’re worried about prostate cancer, talk to you GP. Symptoms such as problems urinating, pain, tiredness, and loss of appetite, should always be investigated. There’s a blood test, called a PSA test, that can be used to screen for prostate cancer in men without any symptoms. However, there are pros and cons to having this test. Your doctor can help you decide if it’s worth you getting tested. BMJ Group News