THE "NEW" PROSTATE CANCER INFOLINK

The Cochrane reviews are widely considered to be among the most rigorous, systematic, and objective reviews of data related to specific medical topics. An initial Cochrane review of data on screening for prostate cancer was carried out in 2006, and it was updated in June 2009.

The objective of the review was straightforward: “To determine whether screening for prostate cancer reduces prostate cancer-specific mortality, impact on all-cause mortality, and patient health-related quality of life.”

The Cochrane reviews are carried out according methods specified in the Cochrane Handbook for Systematic Reviews of Interventions. At least in theory, the rigorous application of predetermined methodology for conduct of such reviews should remove the personal opinions and biases of individual scientists and clinicians in the data compilation, development, and writing of such reviews.

In the case of this particular review, published data were included only if they came from reports of randomized, controlled clinical trials that examined screening vs no screening for prostate cancer in defined populations.

Ilic et al. have recently published a version of the results of the most recent Cochrane review in BJU International. The obsessive reader may wish to compare the abstract of the paper in BJU International with the abstract of the actual Cochrane review.

According to Ilic et al., at the time of their most recent update, they were able to identify just five randomized, controlled clinical trials than met Cochrane criteria for review. The five clinical trials did include the PLCO and the ERSPC trials. These five trials did not include — as an independent study — the Göteborg screening trial published by Hugosson et al. in 2010. However, it is important to understand that the Göteborg data were, in fact, included in the Swedish regional component of the ERSPC. The five trials also did not include the recently published Norkopping data (also from Sweden) — although we are uncertain whether the data from that study would meet Cochrane criteria for review.

Here is a summary of the findings of the Cochrane review:

• The five eligible trials included a total of 341,351 participants.
• All five trials involved PSA testing, but the intervals and thresholds for further evaluation varied from trial to trial.
• The ages of participants ranged from 50 to 74 years.
• Patient follow-up was a brief as 7 years and as long as 15 years.
• The methodological quality of three of the studies appeared to pose a high risk of bias.
• Meta-analysis of data from the five studies showed no statistically significant difference in prostate cancer-specific mortality between the men randomized to screening and the men in the control groups (relative risk [RR] = 0.95).
• Sub-group analyses indicated that prostate cancer-specific mortality was not affected by the age at which participants were screened.
• A pre-planned analysis of a “core” group of men aged between 55 and 69 years from the the ERSPC trial (the largest of the the five trials) reported a statistically significant 20 percent relative reduction in prostate cancer-specific mortality.
• The number of men diagnosed with prostate cancer was significantly greater in men randomized to screening compared with those randomized to control (RR = 1.35).
• Harms of screening included high rates of false-positive results for the PSA test, over-diagnosis, and adverse events associated with TRUS-guided biopsies such as infection, bleeding, and pain.

The original 2006 Cochrane review had concluded that there was “insufficient evidence to either support, or refute, the use of routine mass, selective or opportunistic screening for prostate cancer.”

In this report published in BJU International, the authors conclude  that, “Prostate cancer screening did not significantly decrease all-cause or prostate cancer-specific mortality” based on a combined meta-analysis of data from the five randomized, controlled clinical trials.

The authors also note that, “Any benefits from prostate cancer screening may take >10 years to accrue; therefore, men who have a life expectancy of < 10-15 years should be informed that screening for prostate cancer is not beneficial and has harms.”

It is somewhat puzzling to The “New” Prostate Cancer InfoLink why Ilic et al. should publish this article in BJU International nearly 2 years after completion of the formal update to the Cochrane review itself. The article was accepted for publication in November 2010, some 16 months after the update of the original Cochrane review.

Filed under: Diagnosis, Living with Prostate Cancer, Management, Risk Tagged: | Diagnosis, mortality, PSA, risk, screeing, testing