New NEJM Study on Prevalence of Prostate Cancer among Men with
PSA Levels of 4.0 and Under
The study has and continues to attract significant attention from the news media.
We have known for many years that prostate cancer can be present in men at relatively young ages, and increases with frequency as those men get older. A recent New England Journal study stated that autopsy studies have shown small prostate cancers in up to 29% of men 30-40 years of age. Many of these cancers never become a problem, as evidenced by the fact that the known risk of diagnosing prostate cancer is 1 in 6, while the chances of dying from prostate cancer is 1 in 30.
This current study looks at almost 3000 men who participated in a prostate cancer prevention trial, and who never had a PSA test above 4.0, or an abnormality found on rectal examination during seven years of study. All of these men, whose age ranged from 62 to 91 years, agreed to have their prostates biopsied at the end of the study.
Of this group, about 15% of the men had a prostate cancer. Of those men, another approximately 15% (or 2.3% of the total group) had a prostate cancer with a marker of aggressiveness (called the "Gleason Score") that would be in the range where a doctor would be concerned that the prostate cancer could spread and cause medical illness. Looked at another way, 2501 men had no evidence of any cancer on biopsy of their prostate glands.
This study confirms the knowledge that many men have prostate cancer, even when their examinations are normal. The study does not indicate what would happen to those men if they had not been diagnosed (because of their normal PSA and DRE) or if the diagnosis had been delayed until the PSA was over 4.0.
There have been several studies recently suggesting that the "normal" PSA of 4.0 will miss the early diagnosis of many prostate cancers. This has led to intense discussion regarding lowering the normal PSA level, perhaps to 2.5, which will detect more prostate cancers but also lead to many biopsies of normal prostate glands where no prostate cancer is present. In addition, we are still awaiting the results of a long-term clinical trial looking at the impact of PSA on early prostate cancer detection and treatment.
For patients and their families, the best recommendation remains they should have an informed discussion with their doctor or other health care professional regarding the PSA test, and how to interpret the results and whether further investigation would be appropriate.
For men at average risk, the decision to further evaluate a man depends on several factors, including his age, his PSA level, his general physical health and life expectancy, and what he will do with the information provided by the test.
There is no single "one size fits all" approach to this question. A man who is age 50 and in good health with a PSA of 0.7 would probably not benefit from a biopsy, while a similarly aged man with a PSA of 2.5 should be considered for further investigation. Similarly, a 90 YO man with a PSA of 2.5 would probably not benefit from further investigation.
However, it needs to be emphasized that each decision is based on personal factors and informed discussion of the options with a knowledgeable health care professional.
For the future, we need to continue to refine our understanding of PSA and the new PSA-type tests that are available. We also need better methods, currently under investigation, to determine which prostate cancers will cause problems, and which won't.
Note: The American Cancer Society currently has 64 multi-year prostate cancer research grants-in-effect totaling $32.5 million. Twenty-nine grants were awarded in FY 2003 including the newly awarded clinical research professor in prostate cancer, Kenneth J. Pienta, MD.
Source: The above statement is from Len Lichtenfeld, MD, head of the Cancer Control Sciences Department at the National Home Office of the American Cancer Society. For additional information or support, please contact the NHO Media Relations staff.
Procrastination is the thief of time. - Edward Young