If a man aged 55 to 74 has a low PSA (prostate-specific antigen) and receives aggressive prostate cancer screening, evaluation and treatment, his chances of receiving any benefit are negligible, according to a study published in the medical journal Cancer.
Pim J. van Leuwen, MD, Erasmus University Medical Center, Rotterdam, Netherlands, and team found that males with low serum PSA levels often undergo biopsies and aggressive treatments, with no significant improvement in mortality, after examining details on 85,000 males aged between 55 and 74 years.
Dr. Pim van Leeuwen said:
Screening for prostate cancer has the potential to reduce prostate cancer mortality, but there is a large group of men with a moderately low PSA that will hardly have any benefits of further screening and early detection strategies.
In these men, screening and early detection is likely to have little effect on the reduction of prostate cancer mortality, but a major negative effect on the quality of life.
The authors report than between 1993 and 1999, 43,987 males (aged 55-70) were included in the intervention arm of the ERSPC (European Randomized Study of Screening for Prostate Cancer) section in Finland, the Netherlands and Sweden. 42,503 males (55-74 years) were included in a clinical population in Northern Ireland. PSA <20.0 ng/mL was measured in all the males at study entry. They were all followed-up for prostate cancer incidence and causes of death through to the end of 2006. For males with PSA levels below 2 ng/mL, in order to prevent just one prostate cancer death, 24,642 patients would need to be screened and 724 patients would need prostate cancer treatment. For men with PSA levels between 10 and 19.9 ng/mL, 133 patients would need to be screened to save one life. The authors concluded:
For men with a low serum PSA level, the benefits of aggressive investigation and treatment may be limited because they are associated with a large increase in cumulative incidence and potential overtreatment.
Although prostate cancer is the most commonly diagnosed male cancer, and the third leading cause of male cancer deaths in North America and Europe, the majority of males with prostate cancer do not die from it. In the USA a man carries an average 15.8% risk of being diagnosed with prostate cancer; however, his risk of dying from it is just 2.8%.
Prostate cancer only affects males. Cancer begins to grow in the prostate – a gland in the male reproductive system.
The prostate is an exocrine gland of the male reproductive system, and exists directly under the bladder, in front of the rectum. An exocrine gland is one whose secretions end up outside the body e.g. prostate gland and sweat glands. It is approximately the size of a walnut.
The urethra – a tube that goes from the bladder to the end of the penis and carries urine and semen out of the body – goes through the prostate.
There are thousands of tiny glands in the prostate – they all produce a fluid that forms part of the semen. This fluid also protects and nourishes the sperm. When a male has an orgasm the seminal-vesicles secrete a milky liquid in which the semen travels. The liquid is produced in the prostate gland, while the sperm is kept and produced in the testicles. When a male climaxes (has an orgasm) contractions force the prostate to secrete this fluid into the urethra and leave the body through the penis.
As the urethra goes through the prostate: the prostate gland is also involved in urine control (continence) with the use of prostate muscle fibers. These muscle fibers in the prostate contract and release, controlling the flow of urine flowing through the urethra.
The Prostate Produces Prostate-specific antigen (PSA)
The epithelial cells in the prostate gland produce a protein called PSA (prostate-specific antigen). The PSA helps keep the semen in its liquid state. Some of the PSA escapes into the bloodstream. We can measure a man’s PSA levels by checking his blood. If a man’s levels of PSA are high, it might be an indication of either prostate cancer or some kind of prostate condition.
It is a myth to think that a high blood-PSA level is harmful to you – it is not. High blood PSA levels are however an indication that something may be wrong in the prostate.
Male hormones affect the growth of the prostate, and also how much PSA the prostate produces. Medications aimed at altering male hormone levels may affect PSA blood levels. If male hormones are low during a male’s growth and during his adulthood, his prostate gland will not grow to full size.
In some older men the prostate may continue to grow, especially the part that is around the urethra. This can make it more difficult for the man to pass urine as the growing prostate gland may be causing the urethra to collapse. When the prostate gland becomes too big in this way, the condition is called Benign Prostatic Hyperplasia (BPH). BPH is not cancer, but must be treated.
Click here to read about prostate cancer in more detail.
Pim J. van Leeuwen MD, David Connolly MD, PhD, Teuvo L. J. Tammela MD, PhD, Anssi Auvinen MSc, PhD, Ries Kranse MSc, Monique J. Roobol MSc, PhD, Fritz H. Schroder MD, PhD, Anna Gavin MD, PhD
Cancer Article first published online: 13 SEP 2010
Written by Christian Nordqvist