Before PSA screening for early detection of prostate cancer, more than two thirds of men treated for the disease had incurable cancer that had spread beyond the prostate at the time of diagnosis and treatment.
Confronting A Problem
It was disheartening and difficult for me as the surgeon to sit at the bedside of patient after patient, telling him and his family: “The surgery was successful but, unfortunately, your cancer has spread beyond the prostate gland.” Clearly, more accurate methods for early detection were needed. Prostate cancer had to be detected in a more curable stage.
Detecting in More Curable Stage
“The relative age-adjusted decline in US prostate cancer mortality from 38.2 per 100,000 men in 1994 (shortly after the introduction of prostate-specific antigen [PSA] screening) to 23.5 per 100,000 men in 2006 is nearly 40%, about 3% per year.
It is not clear to us what factor or factors other than PSA screening could be driving this decline.”Nigel Paneth, MD, MPH; George Vande Woude, PhD, and Eric Kort, MD, Msc from a letter to the editor published in JAMA, March 17, 2010
(Journal of American Medical Association)
At the time, the PSA test existed but was used only to monitor men already in treatment. Clinical studies that I reported in 1991, showed the PSA test was useful as a first-line screening test for prostate cancer and, subsequently the PSA test was approved by the FDA.
Before the PSA era, 42% of patients had cancer that had spread beyond the prostate at diagnosis, and 18% of those patients had the most advanced stage of cancer. By 2006, with PSA screening, the rate of advanced cancer had decreased by 78%, and 91% of new cases were contained in the prostate with only 4% being advanced. Five-year survival is 100% for localized versus 29% for advanced disease.
In 2009, an estimated 192,000 new prostate cancer cases were diagnosed; of these, 27,000 fewer men had advanced disease because of PSA screening. During the PSA era, the prostate cancer death rate decreased by 40% (from 39.3 to 23.6 per 100,000 men).
Approximately 50 million men aged 45 and over live in the US. Among these, 8,000 fewer per year died of prostate cancer in the PSA era. Over a 20 year period, 160,000 men were spared a painful death from prostate cancer in the US alone. Similar trends have been reported from the World Health Organization in countries where PSA screening is practiced.
Using What We Know
Men who have a life expectancy of 10 years or more should have prostate cancer screening with PSA and digital rectal exam beginning at age 40 to assess their risk. The PSA testing should appropriately incorporate “derivatives,” such as PSA velocity (rate of change), PSA density (PSA level in relation to the size of the prostate gland), percentage of free PSA, and perhaps, in the near future, the new pro-PSA blood test. Men who are at high risk, especially those with a family history of early age-at-onset prostate cancer, should begin screening at an age 10 years younger than diagnosis-age of their youngest affected relative, just as is recommended for breast cancer.
With current biopsy information, the men who clearly have aggressive cancer can be identified at the time of diagnosis. It is much harder to identify the men whose cancer may not initially appear to be aggressive but will ultimately develop into aggressive cancer. That “not knowing” is precisely why we cannot sit by and “watch” as curable cancer develops into advanced, incurable cancer Ė as happened before the PSA testing era.
During the past few years, researchers have discovered genetic variants in a manís DNA that, alone or in concert with other genes or environmental factors, predispose to prostate cancer. When we learn how these genes work, we will have important insights into what causes cancer, why it sometimes behaves aggressively and sometimes does not, what determines whether it will respond to radiation, hormones, chemotherapy or other treatments, and even how it might be prevented. In the meantime, we need to use what we know and continually work on gaining more useful information.
Civilized People Value Life
Future study will show that PSA screening and effective treatment can reduce the prostate cancer death rate by half, but it will be too late for some of the men who have been influenced by the publicity against prostate cancer screening.
The notion that a man would be better off not knowing his risk for life-threatening prostate cancer in order to avoid a false alarm is incorrect. Anxiety about abnormal screening results and complications from treatment can be remedied; but death has no remedy.
As regards costs, civilized people value life. If a child falls into a well, hikers are lost on a mountain, or even a dog is on the verge of drowning in a storm sewer; the rescue teams come to save the day. Is it not worthwhile as well to spare tens of thousands of men death from prostate cancer?