Should I Have a PSA Test? Prostate Cancer Screening Explained

最后更新： 8 月 15, 2026

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A large part of my clinic is men who arrived with one number on a health-check report: a PSA above the 4.0 ng/mL cutoff. They are frequently very frightened by the time they sit down, and much of the consultation is spent explaining what that number does and does not mean. So let me start where I start with them.

An elevated PSA usually does not mean cancer. It means the prostate has leaked more of one particular enzyme into the blood than expected — and there are several ordinary reasons for that.

What PSA actually is

PSA stands for Prostate Specific Antigen, an enzyme made only by the prostate, whose job is to liquefy semen after ejaculation. It sits at high concentration inside prostate tissue and at very low concentration in the bloodstream. Anything that disturbs prostate tissue — an enlarged prostate, infection, or even minor manipulation of the gland — lets PSA leak into the blood and pushes the number up. When that happens without cancer being present, we call it a false positive.

Note what the name does 不 say: PSA is prostate-specific, not cancer-specific. That single distinction explains most of what follows.

Why screening everyone is no longer recommended

In 2018 a landmark US review concluded that universal PSA screening is not right for everyone: a modest benefit in men aged 55–69, and no benefit in men aged 70 and above. The reasoning is worth understanding rather than just accepting.

• The point of screening is to find high-risk localised prostate cancer, early enough to treat it successfully.
• Much prostate cancer is indolent — slow enough never to cause trouble. Autopsy studies found that about 33% of men who died of something else had prostate cancer nobody had detected, and it had not harmed them.
• Roughly 1 in 1,000 men screened genuinely benefits.
• False positives lead to biopsies that were not needed — with pain, blood in the urine or semen, and infection — and sometimes to treatment of a harmless cancer, which carries its own risks of erectile dysfunction and urinary incontinence.

Put plainly: screening can save a life, and it can also cause harm to a man who was never going to be harmed by his cancer. That is the trade-off, and it is why the recommendation is a conversation rather than a rule.

Who should start the conversation earlier

The 55–69 window applies to men at average risk. Some men are not at average risk and should raise it sooner, at around 40–45:

• A father or brother who has had prostate cancer
• Men of African descent, in whom prostate cancer occurs earlier and more aggressively
• A known family history of certain inherited cancer syndromes, which is worth mentioning to your doctor

One thing that has changed since 2018

Much of the harm in the list above comes from the assumption that a raised PSA leads more or less automatically to a needle biopsy. That is no longer the case. MRI of the prostate before biopsy can distinguish suspicious areas from an innocent gland, and spares a substantial proportion of men a biopsy they did not need. Where a biopsy is still required, the MRI-fusion transperineal technique targets the suspicious area rather than sampling blindly.

This matters for your decision: the balance of benefit and harm in a 2018 review reflected the pathway as it was then, and the harm side of that equation is smaller now than it was.

So what should you do?

If you are a man aged 55–69, discuss PSA screening with your doctor and reach a decision together, in the light of your own risk and your own view of the trade-off. It is genuinely your choice — there is no single right answer that applies to every man, which is exactly why the guidance stops short of telling you what to do.

And if you have already had a high result, do not panic before you have the full picture: here is what a high PSA actually means and what happens next. Screening is also only worth doing if effective treatment follows a positive result — you can read what that treatment involves on the prostate cancer surgery service page.

如果您对PSA筛查有疑问，或PSA检测结果升高，Soarawee Weerasopone医生将在曼谷医院总部提供专家咨询。. 预约咨询. 如需预约三美泰是拉差医院，请致电泌尿科： 088-022-1445.

PSA筛查常见问题

免责声明 本文由曼谷医院总院的董事会认证泌尿科医师索拉维·维拉索蓬（Soarawee Weerasopone）博士撰写并审核。本内容仅供教育目的，不构成医疗建议。通过私人消息渠道不提供任何医疗建议、诊断或处方。在开始任何医疗治疗之前，请务必咨询合格的医疗保健专业人员。.