The STI Clinic News > Trichomonas and Prostate Cancer: Link Questioned by New Study
# Thursday, November 16, 2017
Posted: Thursday, November 16, 2017 | Categories: General Sexual Health | Women's Sexual Health

Trichomonas and Prostate Cancer: Link Questioned by New Study

Trichomoniasis is a sexually transmitted infection caused by the parasite Trichomonas vaginalis. It affects both women and men and because it can be symptomless, or present with symptoms similar to other STIs, it can be difficult to diagnose.

The good news is that trichomonas is relatively rare in the UK; in a study from the end of last year it was found that only 6,000 cases are reported per annum. The bad news is that this fairly innocuous STI is a risk factor for other serious diseases – although not, as previously thought, prostate cancer.

Back in 2006, a study found that that men infected with the T. vaginalis parasite had a 40% greater chance of developing prostate cancer. In 2012, another researcher claimed to have discovered the "molecular mechanism" causing the association between the two conditions.

For men around the world this was concerning news, trichomonas being a common STI in many countries, and not always easily detected. However, doubt has been cast upon these findings by more recent research, which has challenged the idea that trichomonas could lead to prostate cancer.

A study from last year looked specifically at African American men, amongst whom the prevalence of trichomonas and the risk of developing prostate cancer is higher than average. Ultimately, researchers found no strong evidence to suggest a causal link between trichomonas and prostate cancer in these men.

It’s not clear yet what has caused these contradictory results, but one theory is that the T. vaginalis parasite increases inflammation, and encourages the growth of both benign and cancerous cells. Trichomonas, therefore, may not actively cause the development of prostate cancer, but may contribute to more aggressive forms of it.

In other words, men who are particularly at risk of prostate cancer (whether because of age, lifestyle or family history) may do well to stay cautious about STIs such as trichomonas; however, there’s no need to be overly concerned if you receive a diagnosis. Trichomonas is one of the easier STIs to treat. Typically you take an antibiotic called metronidazole for five to seven days.

What is more concerning is that trichomonas is known to increase the risk of HIV transmission and acquisition in women. The T. vaginalis parasite is thought to increase vaginal shedding in women with HIV, which makes them more infectious.

Going forward, the safest thing to do is to continue to practise safe sex, to familiarise yourself with the symptoms of STIs and to get tested if you think you might be at risk of infection.

Trichomonas, STIs & Safe Sex

The symptoms of trichomonas are similar to chlamydia and gonorrhoea. It is thought that about half of all people infected do not suffer any symptoms, but those who do might experience the following:

  • Abnormal discharge from the penis (thin, white) or vagina (thick, thin, or frothy, yellow or green, unpleasant smell)
  • Pain when urinating
  • Soreness and swelling around the vagina or the head of the penis
  • Men may need to urinate more frequently, and women may experience pain during sex

If you are with a partner who is showing any of these symptoms, you should refrain from sex until they have been tested. If you develop these symptoms you should get tested for trichomonas as soon as possible. Click here to visit our clinic and order a home test kit.

Other STI symptoms to watch out for include:

  • Blisters, bumps or sores around the genitals or anus
  • Itching, tingling or burning around the genitals or anus
  • In women, bleeding between periods or after sex
  • In women, pain in the abdomen

To avoid contracting these kinds of unpleasant symptoms, you should always use condoms for penetrative sex if you aren’t sure your partner is free from STIs. You should also be aware that oral sex can transmit STIs; to stay safe when you aren’t sure about your partner’s STI status, use condoms or dental dams during oral sex.

Avoid sharing sex toys that haven’t been washed between uses, and be aware that condoms can’t provide full protection against diseases like genital herpes or warts, as these are spread by skin-to-skin contact.

If you’ve had unprotected sex recently, or if you have sex with multiple or casual partners frequently, it is a good idea to get tested.


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