Prostate cancer is a major killer, but the jury is out on routine screening
Men should be warned that testing for prostate cancer can lead to unnecessary distress, researchers urge.
While the test is not routinely offered in the UK, men over 45 may request one.
If a man has high levels of the protein prostate specific antigen, a biopsy is carried out, which in most cases shows there is no cancerous growth at all.
A British Journal of Cancer study found for 20% this was a distressing process, and that for some these feelings continued even after a negative result.
Researchers from the University of Bristol are calling for the psychological effects of testing to be clearly explained to men ahead of any investigation.
They followed 330 men throughout the testing process.
"We found that in some men, the psychological effects lasted even after the men were told their biopsy was benign," said Professor Kavita Vedhara, who led the research.
"It's essential that doctors know about this, and that men are fully informed of the psychological challenges they may face during and after a PSA test."
Testing on request
Up to 70% receive a negative biopsy result after having raised levels of PSA. While the protein can be a marker for prostate cancer, it can also be caused by an infection , a non-cancerous enlarged prostate or even recent exercise.
But a major study last year suggested that routine screening could cut death rates by 20%, prompting a review of the current policy of testing on request by the NHS.
A final decision will be taken this year, but a number of experts have expressed doubts about the long-term benefits of screening.
Worldwide, prostate cancer is the second leading cause of cancer death.
Cancer Research UK, which funded the research, said: "This study shows just how important it is that men in their 50s and 60s can talk to their doctors about the pros and cons of having a PSA test and only have the test if they feel it is right for them."
Dr Helen Rippon of the Prostate Cancer Charity noted that the majority of men in the study coped well emotionally with the PSA test and subsequent biopsies.
"However, one in five men taking part in the study reported high levels of distress around the time of biopsy which persisted even after they were told that the test had showed no evidence of cancer.
"It is vital that all men considering a PSA test are fully aware of its impact. We must move swiftly to a position of 'universal informed choice' where all men are made aware of their right to request a test and to be given clear information about its usefulness and limitations so they can decide whether having the test is right for them," she added.