PSA: Friend or Foe?

Maybe you heard media reports earlier this year about PSA testing for prostate cancer. Results published in the March 2009 New England Journal of Medicine involved studies in the United States and Europe comparing men that were or were not screened for prostate cancer with the PSA test.

Despite the initial findings recently available, the studies are ongoing. So far, the results developed from averages in large groups of men, suggest that PSA screening helps some men, but other men then receive treatments unnecessarily.

Statistical interpretations can be confusing and need to be carefully evaluated. A study of 77,000 men in the United States indicates that regular PSA screening did not save a significant number of lives over 10 years. A study of 182,000 men in Europe suggests a 20 percent reduction in deaths among those screened regularly. In that study, according to researchers, 48 men had to be treated for every life saved.

Prostate cancer screening, and treatment for that matter, is not an exact science. Variability exists between screening and treatment approaches. It is widely acknowledged that the PSA is an imperfect test, and better diagnostics and interpretations of results are needed to avoid unnecessary treatments. However, the PSA test still has value to some men. Beyond the news stories discouraging men from prostate cancer screening, APCaP wanted to provide additional perspectives— prostate cancer survivor advocates and urologists.

Survivor and Patient Advocate Perspective by Terry Roe
Media stories suggest that prostate tests save few lives and screening can lead to risky and unneeded treatments as their predominant message about recently published studies on the PSA.

Running through the news articles is a fascination with numbers, not human lives. “But the number of lives saved was small— seven fewer prostate cancer deaths for every 10,000 men screened,” states one news article. Examining this criterion for 259.000 men screened, the “small” figure was 206 lives— men who might be fathers, sons, or dear friends.

According to the American Cancer Society’s Cancer Facts & Figures 2009, the dramatic improvements in prostate cancer survival, particularly at 5 years, are partly attributable to earlier diagnosis and improvements in treatment. Over the past 25 years, the 5-year prostate cancer survival rate for all stages combined has increased from 69 percent to almost 99 percent. Relative 10-year survival is 91 percent and 15-year survival is 76 percent.

What is the value of one human life, or ten, or 100, or 200, 1,000, or more? PSA testing clearly saves some lives. This point is deemphasized in media stories about the study results.

In some if not many news reports, there was no mention of African-Americans or genetically endangered patients with inherited prostate cancer. Researchers need to measure the efficacy of PSA testing in these specific groups of men. After all, one in four African-American men will be affected by prostate cancer compared to one in six men overall. Inherited prostate cancer accounts for approximately 10 percent of all prostate cancer diagnoses, and as many as 43 percent of prostate cancer cases diagnosed before age 55. In African American men, the chances of prostate cancer are one in three (33 percent) for men with one close relative with the disease, 83 percent with two close relatives, and 97 percent with three close relatives.

As an 18-year prostate cancer survivor, I know that most of the survivors involved with our organization recognize benefits from the PSA test, imperfect as it may be. To frighten off men until another test is developed would be a tragedy.

For years APCaP has urged men to be screened at the appropriate age, to obtain a baseline PSA, and to be screened periodically depending on their condition. APCaP board members have attended American Urological Association meetings with discussions about the impact of PSA increases over time (velocity) and whether a PSA score of four or two should be considered a tipping point, among many other topics. Research continues to reveal more information about the best ways to understand and utilize PSA testing. Men need to educate themselves about the overall pros and cons, ask their doctors questions, and collect multiples opinions when necessary.

Some men may decide not to be screened with PSA at all. What else does that leave for prostate cancer screening? APCAP recognizes that PSA testing may result in unnecessary treatments, and calls for better interpretations of findings to distinguish between benign and malignant to avoid over-treatment. Until more reliable screening approaches are widely available, APCaP strongly recommends prostate cancer screening with the PSA.

APCaP’s Scientific Advisory Board provided the following comments and perspectives about the recently published European and American studies on the PSA.

Phillip Kantoff, MD, Dana Farber Cancer Institute
These studies are difficult for many to reconcile, but they do not resolve the screening controversy. Specifically, the PSA is the best test we currently have for detecting prostate cancer and it is likely that its use reduces mortality from prostate cancer. On the other hand, PSA testing leads to many unnecessary biopsies and to the diagnosis of prostate cancer in men who would not die of the disease. Until we have better tests for detecting aggressive forms of prostate cancer, we need to carefully separate the diagnosis of prostate cancer from treatment in order to reduce over-treatment.

Paul Schellhammer, MD, E. Virginia Medical School
I believe that the screening trials have provided hard data that supports the concern that many men are not well served by the diagnosis and treatment of prostate cancer. That is not to say however that a number of men do not derive benefit, and the healthcare community cannot ignore this benefit. To maximize the benefit and minimize the harm that might result from the diagnosis of prostate cancer does not, in my opinion, reside in cessation of PSA testing, but does necessitate recognition of the tests limitations, and the need to educate physicians and especially patients about the limitations, and all the while searching for better markers for nonlethal and lethal cancer and more effective treatments for the latter.

In the meantime the dilemma faced by men will continue. Dr.H. Gilbert Welch, author of “Should I be tested for cancer? Maybe not and here’s why” and a physician whose opinion I respect, has noted that his analysis of the data convinces him that he would not have a PSA. I also respect my opinion and I made the decision to have periodic PSA testing. As a result I was diagnosed with prostate cancer, have received in succession surgery, radiation, intermittent and continuous androgen deprivation, second line hormone therapy, and participated in a phase 2 clinical trial. I have no regrets. But it does not matter what Dr. Welch thinks or what I think. Each individual needs to calculate and calibrate his own situation. For some there will be intuitive conviction towards one direction or another, but for others there will be indecision, which, unfortunately, current data cannot entirely resolve.

Nicholas J. Vogelzang, MD, Nevada Cancer Institute
We need better tests than PSA. That having been said, data from studies performed in the United States are still premature and possibly contaminated by screening PSA tests done prior to entry into the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial (PLCO).