Prostate Cancer - Evidence Not Beliefs Matter Regarding Screening And Treatment

Editor's Choice
Academic Journal
Main Category: Prostate / Prostate Cancer
Article Date: 26 Jan 2012 - 6:00 PST

email to a friend   printer friendly   opinions  

According to Beth Israel Deaconess Medical Center and prostate expert Marc B. Garnick, MD, physicians who advise PSA tests for men being screened for prostate cancer must base their decision more on available evidence when recommending screening, biopsies and treatments, instead of holding on to long held beliefs that PSA-based testing benefits all.

Garnick wrote in the February issue of Scientific American, stating that the current system of relying on prostate-specific antigens levels in the blood is "deeply flawed," and physicians must consider that "the PSA test does not tell you if a man has cancer, just that he might have it."

According to the latest US Preventative Services Task Force's evaluation of studies published in 2009, PSA testing demonstrates more harm than good in terms of results. Furthermore, the report shows that in light of the evidence, a more cautious, individualized approach should be taken towards patient treatment, instead of aggressive early treatment for all. The approach is currently underway at BIDMC.

Garnick, who is also an editor-in-chief of Harvard Medical School's Annual Report on Prostate Diseases and related website, states:

"Most people outside the medical community do not realize how flimsy evidence has been in favor of the PSA screening data. In a perfect world, a screening test would identify only cancers that would prove lethal if untreated. Then, men who had small, curable cancers would be treated, and their lives would be saved. Ideally, the treatments would not only be effective, they would have no serious side effects. Such a scenario would justify massive screening and treatment of everyone with a positive test."

At present, however, there is no reliable approach for doctors to determine which of these small cancers identified by biopsy are potentially dangerous and which remain harmless throughout life. Additionally, all treatments currently available pose substantial risks and long-term side effects.

Garnick says that the number of men who would need to receive treatment, and potentially suffer the consequences of the treatment to successfully prevent just one single prostate cancer death, has prompted the Task Force to recommend against wide spread PSA testing for all those without symptoms of prostate cancer.

Two 2009 studies, one in Europe and one in the US, randomly divided healthy men in their 50s and 60s into two groups. One group was periodically screened for prostate cancer using PSA testing, adigital rectal exam or both, whilst the other group received standard medical care as required without being offered routine testing.

The European study revealed that only those tested and treated for prostate cancer had a mortality risk of 20%, although such a decrease was not observed in the U.S. study. Neither study demonstrated whether those who were tested and treated had a longer life expectancy, compared with those not offered routine testing.

The researchers in the European study established that about 1,400 men would have to be screened to prevent one single person from dying of prostate cancer, and result in 48 others needing to undergo treatment, whilst the other 47 men would be likely to suffer serious side effects, like incontinence and impotence, due to the radiation or surgery.

Garnick explains:

"The overall death rate from all causes was not statistically different in both the screened and unscreened groups. Unfortunately, the mortality data collected over the past 25 years shows that the natural history of prostate cancer is not as straightforward as my colleagues and I once believed. Many cancers will never cause problems during the patient's lifetime, and hence do not need to be treated, at least immediately."

According to findings from a long-term Canadian study, the prostate cancer mortality rate for those men who chose active surveillance or delayed treatment following PSA testing resulted in a cancer diagnosis of 1% over 10 years in comparison to a 0.5% mortality risk due to post prostate cancer surgery complications within one month after surgery.

Garnick declares:

"The point is that the initial decision to forgo treatment is not necessarily the final one. Surgery, radiation and other therapies are still available later on, and most current data indicate that the outcome will not be negatively affected by the delay. Such an approach is improving our ability to tailor treatments for individuals rather than always treating everyone the same."

The results of this decision suggests that doctors, as well as patients both need a precise scientific understanding about these issues, in particular during a doctor-patient discussion. Garnick comments: "We need to have the courage to act on the evidence and not just our beliefs."

Written by Petra Rattue
Copyright: Medical News Today
Not to be reproduced without permission of Medical News Today

• Additional
• References
• Citations