Should we screen for prostate cancer?
Responsible for 10,000 deaths annually, prostate cancer is the leading male cancer in France. Yet, faced with this problem, the utility of mass screening remains controversial. Beneficial for some, useless and dangerous to others … Published in late March 2009, two major studies (one American and one European) would enable a clearer picture.
There are in France more than 40 000 new cases of prostate cancer annually. Thus the first human cancer, to lung cancer. Like breast cancer for women, a man about 9 present a clinical form of the disease during his lifetime. This disease is responsible for 10,000 deaths per year in France.
1. Obstacles to screening for prostate
Based on the adage that more cancer is detected early, the better it is processed, the screening of prostate cancer has rapidly been a topic of public health. But such screening is hampered by several obstacles as sociological than scientific.
On the one hand, men are less accustomed to submit to screening, unlike women who are willingly submitting to thanks from a young age (smear, palpation, mammography …). As pointed out a study of the French Association of Urology, though women have learned to manage their sexual health, men are still reluctant to talk about it. A word more difficult to clear they have no interlocutor, unlike women who listen to the gynecologist.
But it is the very usefulness of screening and its tools at the heart of a controversy redundant.
2. Screening worthwhile?
A mass screening should be based on a simple, economical, non-hazardous and should lead to a reduction in mortality from the disease focus. For prostate cancer, the test in question is the PSA, a prostate protein whose rate increases in blood cancer cases. Problem: this test features a higher risk but can not make a diagnosis. For this, a biopsy is necessary. But this invasive test can then detect prostate cancers are indolent and which may have remained devoid of symptoms …
In July 2007, two specialists Catherine Hill and Professor Gerard Dubois felt that mass screening would lead to over-diagnosis and therefore treatment unnecessary and not without side effects. According to their calculations, a screening of the 7 million men aged 50 to 75 years would lead to 336 000 positive tests (12%), to discover 70 000 cancers, of which approximately 30% of cases that would never become symptomatic.Following treatment, 33 000 men (45%) had problems of impotence, incontinence or proctitis. Results that have earned them the wrath of the French Association of Urology who recalled that one such screening could identify certain cancers very active and very dangerous but which are 95% curable if detected early.
Today, the BAS recommends testing (and remember this message on the occasion of a national day dedicated to the prostate), while InCA and HAS do not recommend it for lack of evidence of a decrease mortality related to screening.
2. Screening for prostate cancer: the controversy continues …
Only large-scale studies showing the influence of screening on mortality could settle this debate redundant. And late March, the two studies (American and European) were finally published in The New England Journal of Medicine!
The study conducted in eight European countries (including France) was initiated in 1990 and covers more than 160 000 men aged 55 to 69 years. Half have been screened, the other not. Preliminary results as at 31 December 2006 reveal a decrease in deaths from prostate cancer by 20% in the screened cohort. Twice as many cancers were diagnosed among screened men. The authors estimate that 1408 men should be screened for PSA, 48 cancers were detected and in the end death is avoided. Moreover, the benefit of screening appears only in the age group 55-69 years.
End of controversy? Not really, since the U.S. study (conducted on 76 000 men) do not show benefit on mortality …
While the “controversy refuses to die” (as stated by Michael Barry in an editorial in the same journal), the High Authority for Health (HAS), Institute of Cancer (INCA) and the French Association of Urology should consider these results to develop joint recommendations shortly.