Screening cancro della prostata: attenzione alla disinformazione!
Negli ultimi mesi abbiamo assistito ad una discussione accesa tra sostenitori dello screening precoce del cancro della prostata e i suoi detrattori. Il dibattito è scaturito da alcune raccomandazioni della Food and Drug Administration americana (attraverso una delle sue agenzie).
Gli urologi sono convinti che la diagnosi precoce del tumore della prostata aiuti a salvare vite e che il fatto che il PSA non sia un testo perfetto non giustifica il suo abbandono.
Questo è il testo ufficiale dell’american urological association sull’argomento che invita alla cautela e a proseguire l’opera che migliaia di medici continuano a svolgere in tutto il mondo.
November 8, 2011
Virginia Moyer, MD, MPH
U.S. Preventive Services Task Force
c/o Dr. Robert Cosby
540 Gaither Road
Rockville, MD 20850
Dear Dr. Moyer,
On behalf of the more than 13,000 urologists and urologic health professionals in the United States whom we represent, the American Urological Association would like to submit our comments on the U.S. Preventive Services Task Force’s Draft Recommendations on Screening for Prostate Cancer.
It is the opinion of the American Urological Association that these recommendations, in their current form, do a great disservice to the many men in this country who could benefit from talking with their doctors about prostate cancer. Prostate cancer is a potentially devastating disease that is best managed when caught early. Though we are well aware of the limitations of the serum prostate-specific antigen (PSA) test, we are unable to appropriately manage those tumors that we do not know exist. It is the PSA test that has allowed us to move beyond a time when men presented with high-grade, metastatic disease for which there were little or no treatment options beyond palliative care. In its earliest stages, most prostate cancers cause no symptoms; to say that only men with symptoms of prostate cancer should be tested will potentially result in a return to such a time.
We recognize the Task Force’s concerns about over-diagnosis and treatment, and understand that overtreatment of over-diagnosed prostate cancers is common (90 percent of men with detected prostate cancer receive some form of treatment). We also recognize that, in some cases, treatment of prostate cancer can result in serious harm without any benefit for those who are over-diagnosed and over-treated. However, we stand firmly in our belief that the PSA test – when used and interpreted appropriately – provides valuable information in the diagnosis, pre-treatment staging or risk assessment and monitoring of prostate cancer, especially in younger men.
However, we also agree that the current “one size fits all” approach to screening (testing men annually, testing men in their 70s more often than men in their 50s) leads to over-diagnosis of cancers that would otherwise not have been detected during life. Screening less frequently or not at all for those men with low PSA levels and those who are older and in poor health, would reduce over-diagnosis. We need a new testing paradigm – and a more specific biomarker – to better target those men who can benefit from testing.
Simply put, just as it is inappropriate to issue a “one size fits all” pro-screening message, it is equally inappropriate, and potentially irresponsible, to issue a blanket statement against testing, as studies have demonstrated strong benefits to prostate cancer screening. We believe that there is strong evidence that, for some men – generally those younger and in good health – testing saves lives. Men who are in good health and have more than a 10-15 year life expectancy should have the choice to be tested and not discouraged from doing so.
The randomized trials quoted by the Task Force do, in fact, show a benefit to younger patients. The PLCO Trial, imperfect by the pre-screening contamination of the control arm, nonetheless showed that, in a group of young men with minimal or no comorbidities, there was significant reduction of prostate cancer death rates after a median follow-up of seven years (JCO 2011;29:355-361). Additionally, the Göteborg Trial also showed a substantial 44 percent relative risk reduction in prostate cancer mortality occurring in men 50-64 years of age after a median of 14 years. Importantly, the risk reduction occurred in a setting where many of the patients were not aggressively treated for prostate cancer, indicating that the harms of PSA-based screening can, in fact, be minimized by good clinical practice (Lancet Oncol 2010;11:725-732). Furthermore, we have seen a 40 percent reduction in prostate cancer-specific mortality in the United States over the most recent 20 years of PSA-based screening. This has occurred without substantial change in how men with prostate cancer were treated (primarily with surgery and radiation therapy). Models have suggested that more than 50 percent of this reduction is due to early detection (Cancer Cases Control 2008;19:175-181).
Rather than instruct primary care physicians to discourage men from having a PSA test, the Task Force should instead focus on how best to educate primary care physicians regarding targeted screening and how to counsel patients about their prostate cancer risk. Likewise, we also need to demonstrate to patients how active surveillance may be more appropriate than immediate treatment, and how this approach helps reduce the harms of screening. In fact, the AUA has convened a team of clinical experts to develop a guideline on the Detection of Prostate Cancer, which, when released, will provide critical guidance to the medical community on these issues.
Issuing a “Grade D” recommendation for the PSA test sets a course that may, in fact, do more harm than good. The screening trials previously mentioned are very early in their analysis, but appear to show quite clearly that young men benefit most from PSA screening. This test has allowed early diagnosis of a cancer that, when confined to the prostate, is still curable, but when outside the confines of the prostate, is not. We believe that disparaging the PSA test does a great disservice to our patient population and that it is not the PSA test itself – but rather what is done with the information – that has created much of the controversy. The future should involve screening a more focused, healthy population, with a contemporary discussion of all therapeutic options, including active surveillance by knowledgeable providers, and integrating better molecular markers and imaging into the decision pathways.
The AUA would welcome the opportunity to work with the Task Force on revising its recommendations to ensure that we move forward, not backward, in our fight against prostate cancer.
8 Novembre 2011