A 20-year study to determine whether screening men for prostate cancer prevents deaths, has concluded that it is of no value. The trial began in Sweden in 1987 and involved 9,026 men. More than 1,400 men had screening tests every third year and the remaining men did not.
The first two screenings were done by digital rectal thermometer and then after 1993, this was combined with prostate specific antigen testing (known as PSA testing). PSA testing is supposed to help a doctor find out how likely a man is to develop prostate cancer. It is available to men if they are worried about prostate cancer, for instance, due to having a family history of it. A high level of prostate specific antigens is thought to indicate cancer, but this is speculative because all men have different levels of PSA anyway so it is not known what a high level is. PSA levels can also increase due to other reasons such as:
• Recent sexual activity
• Prostatic hyperplasia (a non-cancerous enlargement of the prostate gland)
• Vigorous exercise.
There were 85 cases of prostate cancer in the screened group (the smaller group) and 292 cases in the placebo group, meaning that those who were screened had a higher rate of cancer (5.7 percent vs. 3.9 percent). The risk of death from the disease was similar in both groups.
The study authors concluded:
‘After 20 years of follow-up the rate of death from prostate cancer did not differ significantly between men in the screening group and those in the control group.’
In fact, the PSA test leads to an alarming number of false positives that mean a risk of over-diagnosis and over treatment. The treatments themselves can lead to devastating side effects, which, if not needed, may be truly tragic for the patient and his family.
Professor Malcolm Mason, Cancer Research UK's prostate cancer expert, commented: "This trial found that screening did not reduce deaths from prostate cancer and there is no escaping from the fact that we need a better tool than PSA to help detect prostate cancers that actually need treating, as opposed to innocent ones that do not ... In the meantime, men should be fully informed about the pros and cons of having their PSA measured."
Sources: Sandblom, G., Varenhorst, E., Rosell, J., Lofman, O., & Carlsson, P. (2011). Randomised prostate cancer screening trial: 20 year follow-up BMJ, 342 (mar31 1) DOI: - http://www.bmj.com/content/342/bmj.d1539
Cancer Research UK.
Joanna is a freelance health writer for The Mother magazine and Suite 101 with a column on infertility, http://infertility.suite101.com/. She is author of the book, 'Breast Milk: A Natural Immunisation,' and co-author of an educational resource on disabled parenting, in addition to running a charity for people damaged by vaccines or medical mistakes.