False positives

Tests are based on prostate-specific antigen (PSA) blood levels. About 80% of positive results are false positives, which causes a lot of unnecessary anxiety.


An abnormal PSA typically requires further testing – either a biopsy or ultrasound. Both are uncomfortable and can cause problems such as infection.


About 75% of prostate cancer cases are not fatal even if left untreated, while 25% are aggressive killers. But we can’t yet reliably distinguish between them. Surgery, radiation and hormone therapy have significant side effects such as incontinence, infection and permanent impotence. Knowing the risks, many doctors opt for a strategy called ‘watchful waiting’, in which an elevated PSA level is tracked every three to six months and treatment is recommended only if there is a rapid or large rise (suggesting the cancer may be an aggressive one).

Know your risk factors

These include age (most prostate cancers are diagnosed over age 65); ethni­city (risks are higher for people of African descent compared to Caucasians, lower for Asians, Indigenous Australians and Pacific Islanders); and family history – your risk is significantly higher if you’ve had two or more relatives diagnosed, especially a father or brother diagnosed when younger than 65.

Get the digital rectal exam

It’s an annual check for over-50s, but start earlier if you have risk factors.

Balance the risks

Talk to your doctor about the implications of false positives, over-diagnosis and over-treatment and have a plan of action in place before you test.

Reduce false positives

Certain things increase PSA levels, including low-grade trauma to the prostate (such as a recent rectal exam or long bike ride) and ejaculation. Avoid all for at least 48 hours before the test.

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