Prostate cancer screening and early detection

Introduction

The issue of whether men should get regularly tested for prostate cancer is highly controversial and all too often gives rise to very strong emotions. For some very obvious reasons those patients who have been diagnosed early and successfully treated for prostate cancer clearly believe in the widespread use of “screening.” On the other hand, two large, randomized, but certainly flawed clinical trials have shown that such widespread, population-based “screening” has (at best) limited impact on the long-term, average survival of men in a defined population.

People often get confused about the difference between screening for prostate cancer and early detection of the disease. It happens to professionals and to patients. Let’s see if we can help to make the difference clear.

The Brownsville Experiment

Dr Brown, a urologist, wants to find how many men in Brownsville have prostate cancer.

The first year — Dr Brown decides that in order to answer his question he will give a free digital rectal examination (DRE) and PSA test to every fifth man over 40 years old who walks past his office on main street on a Saturday morning in May. He then gives a biopsy to every man with either a positive DRE or a PSA level > 2.5 ng/ml. In other words, these men are picked completely at random — except that they must walk past his office and be over 40. This is a true, population-based, prostate cancer screening program. The men have been selected at random from all men in Brownsville that day, and they don’t necessarily even think that they should be having a prostate cancer test.

The second year — A screening program like the one he does in the first year takes a lot of effort, so the next year Dr Brown decides just to offer a free DRE and PSA test to any man over 40 who comes to his office on the same Saturday morning in May and asks to be tested, and then to biopsy the men according to the same criteria as in year 1. So he puts an ad in his local Brownsville newspaper. This year, the people who get the DRE and the PSA test have selected themselves for some reason. Maybe they just think its time they had a PSA test. Maybe they have had to get up a few times too often in the middle of the night. Maybe their wife told them it was high time they had a prostate cancer test. Or maybe they just thought that they’d have the tests while they were free. Some physicians now call this case finding. It certainly isn’t a true screening initiative, because the tests aren’t being given at random and the men who get the tests have selected themselves.

The third year — Finally, the third year, Dr Brown decides he isn’t going to give anything away for free. Instead, he will encourage every man over 40 who comes to his office to have a DRE and a PSA test, regardless of their symptoms. His justification for this is that if they have come to see him — a urologist — there is good reason to think that they may have a urological disorder, including prostate cancer. This is true early detection. In other words, Dr Brown is going to do his best to find prostate cancer in any patient who comes to see him, but he isn’t going to go out of his way to look for patients with the disease.

Recommendations for Prostate Cancer Testing

There is now some good information to suggest that mass, population-based screening for prostate cancer can make a difference to how long men in a defined population will live if they are all regularly tested for prostate cancer. Studies completed in the Tyrol region of Austria and in King County, Washington in the USA provide evidence for the possible benefits of population screening.

Having said that, the recent results of the Prostate, Lung, Colorectal and Ovarian (PLCO) cancer screening trial in the USA and the European Randomized Study of Screening for Prostate Cancer (ERSPC) in Europe suggest that, while population-based screening for prostate cancer may be able to make a small difference to overall mortality from prostate cancer, this reduction in mortality may also come at a high cost in terms of the over-diagnosis and over-treatment of men who have forms of prostate cancer that are unlikely to ever be clinically evident.

Interpretation of the data from these two trials is complicated by many factors. In order to get a sound understanding of what these two trials have shown, we recommend that interested readers also:


Just click here to watch a brief video presentation
about the pros and cons of prostate cancer screening.

What is truly sad, however, is the inability of the various factions within the medical community to put aside their relatively trivial differences and issue one, simple consensus statement for patients about the testing of individuals for risk for prostate cancer. This failure to recognize the utter confusion of patients on this issue is a sad comment on the divisions within organized medicine. It will perhaps never be resolved until we can clearly identify a much better way to test for clinically significant prostate cancer (cancer that places a man at individual risk for progressive disease that may lead to metastasis and prostate cancer-specific death).

Recommendations of the American Cancer Society — In March 2010, to coincide with a Congressional hearing on prostate cancer (according to their chief medical officer), the American Cancer Society (ACS) released new guidelines on “screening” for prostate cancer that have met with nearly as much controversy as the guidelines they released on screening for breast cancer in 2009. Here are:

In fact, what the American Cancer Society is now saying is arguably not that different from what they have said for several years — which is that any man who wishes to be tested for his risk for prostate cancer should do so only after an individual discussion of his personal risk with his primary care physician. If this was all they had in fact said, the “New” Prostate Cancer InfoLink would not have a problem with the new ACS guidance. However, they made a number of other statements in their guidance which are distinctly questionable, specifically including reference to the appropriateness of 4.0 ng/ml as a “cut-off” value for referral for a biopsy and the idea that a digital rectal examination is “unnecessary” as part of regular testing for prostate cancer risk.

The “New” Prostate Cancer InfoLink is increasingly puzzled by what the ACS seems to consider its mission to be. In recent years the ACS seems to have become a great deal more motivated by raising money to fund research than it is by the idea of helping individual patients to get truly sound and understandable information. We are all in favor for funds for cancer research … but the primary intent at the end of the day should be to help patients, not just fund research!

Recommendations of the US Preventive Services Task Force — In the most recent (August 2008) revision to its guidelines on prevention of prostate cancer (published before the results of the PLCO and ERSPC trials were available), the US Preventive Services Task Force (USPSTF) had indicated that “the current evidence is insufficient to assess the balance of benefits and harms of prostate cancer screening in men younger than age 75 years” and that “The USPSTF recommends against screening for prostate cancer in men age 75 years or older.

This does not mean that men with possible symptoms of prostate cancer should not be tested. It does mean that a large sector of the medical community still does not endorse annual PSA tests and physical examinations for asymptomatic males.

In the “Suggestions for Practice” included in their recommendations statement, the Task Force wrote:

Given the uncertainties and controversy surrounding prostate cancer screening in men younger than age 75 years, a clinician should not order the PSA test without first discussing with the patient the potential but uncertain benefits and the known harms of prostate cancer screening and treatment. Men should be informed of the gaps in the evidence and should be assisted in considering their personal preferences before deciding whether to be tested.

Recommendations of the American College of Physicians — The American College of Physicians (one of the largest organizations of primary care physicians in the US) published a series of detailed articles on prostate cancer in the Annals of Internal Medicine in early 1997. However, they have not updated their recommendations for 12 years.

Recommendations of the American Urological Association — The American Urological Association (the AUA) is the national organization representing most of the urologists in America. This group completely overhauled its “best practices statement” in late April 2009 — after the publication of the PLCO and ERSPC data. This best practices statement is complex and detailed, and it is impossible to summarize in a single bullet point, but here is our understanding of the key points, using the words the AUA itself uses in its guidance document:

  • “The AUA is recommending PSA screening, as proposed in this document, for well-informed men who wish to pursue early diagnosis.” [The italic type is included for emphasis in the actual AUA best practice statement.]
  • “The goal of early detection is to reduce the overall morbidity and mortality of prostate cancer.” (In other words, the goal of early detection is not to find every single man who may have some cancerous cells in his prostate. Early detection is about identifying those men who are at risk for clinically significant disease as early as possible.)
  • “The proportion of clinically significant prostate cancer detected with PSA is unknown.” (In other words, we cannot rely on the PSA test alone to tell us which men have clinically significant disease and which men do not.)
  • “Men who wish to be screened for prostate cancer should have both a PSA test and a DRE.” (This has been the standard of care for initial assessment of potential risk for prostate cancer since the PSA test was introduced as a means to detect risk, and remains the standard today.)
  • “Although testing for PSA involves only a blood test, several subsequent events must be considered before the test can be considered innocuous. A positive test result affects patients both mentally and physically even if a patient chooses not to proceed to prostate biopsy.” (This is a critical statement. Fear of cancer is not necessarily rational, and it can drive behaviors that are not necessarily in the best interests of the patient.)
  • “The decision to use PSA for the early detection of prostate cancer should be individualized.” (In other words, the AUA is no longer making any blanket statement about testing of all men. They are saying that every situation has to be considered on its possible risks and its possible benefits.)
  • “Among men in their 40s and 50s, a baseline PSA value above the median value for age is a stronger predictor of future risk than family history or race.” (The best practice statement goes on to indicate that the median PSA value of men in their 40s is 0.6 to 0.7 ng/ml.)

In  a chart that is provided with this guidance document, the AUA further suggests that for well-informed men who believe they are at specific risk for prostate cancer, testing should be initiated as early as 40 years of age.

One last comment about the revised AUA statement. For years people have been under the impression that a PSA value of ≥ 4 ng/ml was “bad” and that a PSA value of < 4.0 was “good.” The AUA has now been very, very clear in stating that:

… the current policy no longer recommends a single, threshold value of PSA which should prompt prostate biopsy. Rather, the decision to proceed to prostate biopsy should be based primarily on PSA and DRE results, but should take into account multiple factors including free and total PSA, patient age, PSA velocity, PSA density, family history, ethnicity, prior biopsy history and comorbidities.

Should You Have Regular Prostate Cancer Tests?

As indicated in the recommendations of the American Cancer Society and the US Preventive Services Task Force, and despite the recommendations of the AUA, there are many physicians who do not believe that regular PSA tests are necessarily a good thing. They argue that while it may be possible to find indications of possible prostate cancer using digital rectal examinations and PSA tests, the really difficult questions are:

  • How hard must we then search to discover whether a particular patient actually has prostate cancer?
  • Does that patient have clinically significant prostate cancer that needs treatment?

and then

  • How should we treat his disease if and when we find it?

An option that some men consider is annual DREs without PSA testing. While there is a good chance that such tests will allow an experienced urologist to detect clinically significant prostate cancer, it is also true that by the time a DRE becomes a certain indicator of probable prostate cancer, it may not be possible to apply potentially curative therapy with confidence.

Ultimately the decision whether you should have regular tests for prostate cancer — and what those tests should be — is a matter for you and your physician. The answer is likely to require careful assessment of your personal attitudes to the risks of cancer, family history of cancer, age, and your other clinical history. In introducing the new AUA best practices statement in April 2009, Dr. Peter Carroll, the chairman of the group who re-wrote the guidance document, made an absolutely crucial comment which is fundamental to the entire evaluation of the new document. He said,

The single most important message of this statement is that prostate cancer testing is an individual decision that patients of any age should make in conjunction with their physicians and urologists.

The “New” Prostate Cancer InfoLink encourages you to talk frankly with your primary care physician about this,  as well as with your urologist if necessary, and to make your decision only when you feel comfortable and “well-informed” about it.

Full Disclosure

The “New” Prostate Cancer InfoLink now believes that men who are considering having a DRE and a PSA test should be fully informed as follows:

  • Prostate cancer is an important health problem, but the value of mass, population-based screening is not yet satisfactorily proven to affect mortality.
  • Although as many as one in six men may be diagnosed with prostate cancer in their lifetimes, this means that five men in six or 83.3 percent will not.
  • Having cancer cells in one’s prostate does not necessarily mean that you will ever have any clinically evident signs or symptoms of the disease.
  • Early detection and treatment clearly does reduce the morbidity and mortality associated with clinically significant and progressive prostate cancer.
  • The decision to undergo testing of risk for prostate cancer is a highly personal decision that should be taken with the best advice and guidance available.
  • Digital rectal examination and PSA measurement can have both false positive and false negative results.
  • The probability that further invasive evaluation will be required as a result of DRE and PSA testing is relatively high.
  • A small but finite risk for early death and a significant risk for chronic illness, particularly with regard to sexual and urinary function, are associated with all invasive treatments for prostate cancer.

Another issue that presents challenges remains the relevance of testing for prostate cancer in men over the age of 75 years. Proposals for how to address this issue were put forward in the so-called “Iowa Prostate Cancer Consensus” in 2008. The “New” Prostate Cancer InfoLink continues to believe that the Iowa consensus is a sound and patient-focused way to address a complex and emotionally problematic issue.

Content on this page last reviewed and updated March 15, 2010.
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