The Prostate, Colorectal, Lung and Ovarian cancer screening trial (the PCLO trial) is the major US trial designed to investigate whether screening for these four cancers actually affects long-term mortality rates, and is the only truly randomized, controlled trial of screening for prostate cancer.
Grubb et al. have just published the most recent update to the progress of this trial with respect to prostate cancer, although it should be stated immediately that we are still many years from learning the impact of prostate cancer screening on mortality.
The prostate cancer component of the PCLO trial is designed to explore whether annual screening with prostate-specific antigen (PSA) and a digital rectal examination (DRE) reduces prostate cancer-specific mortality. The information published by Grubb and colleagues covers the first four completed rounds of screening:
- A total of 38 349 men aged 55-74 years were initially randomized to undergo annual screening (but note that management as a consequence of abnormal screening results was at the discretion of the subjects and their physicians).
- Compliance with screening decreased slightly from 89 percent at the first screen (baseline or T0) to 85 percent at the third follow-up screening test (T3).
- The proportion of patients who have had a PSA level > 4.0 ng/ml (range 7.7-8.8 percent at T0-T3) or a positive DRE rates (range 6.8-7.6 percent at T0-T3) have stayed relatively constant over time.
- The positive predictive value (PPV) of a PSA level of >4.0 ng/ml has decreased from 17.9 percent at T0 to 10.4-12.3 percent at T1-T3.
- The PPV for DRE (in the absence of a positive PSA test) has also remained constant over time (range 2.9-3.6 percent at T0-T3).
- To date, prostate cancer has been diagnosed in 1,902 men (4.9 percent).
- The 549 cancers detected at baseline (T0) were more likely to be clinical stage III/IV (5.8 percent) and to have a Gleason score of 7-10 (34 percent) than cancers detected at later (T1-T3) screening intervals (1.5-4.2 percent stage III/IV and 24-27 percent Gleason 7-10 among 1,054 cases).
Grubb et al. conclude that, so far, the findings on serial prostate screening from the PCLO trial are similar to those reported from other multi-round screening studies.
The projected date for completion of this trial is still 2014, with the earliest expectation for publication of trial results in 2015.
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Thank you.
Please keep these reports coming.
Oh great. Another 6 years + to find out the results of a “study” when empirical evidence has shown a 30% reduction in prostate cancer deaths over the past decade. I’ve said it before and I’ll continue saying — no man has ever been treated for prostate cancer without being diagnosed and no man has ever been diagnosed without being screened. At the current rate almost 180,000 more men will die before this “study” concludes. The best value of this study so far was that 1,902 men were found to have prostate cancer and could decide what action they want to take.
While I have great sympathy with Stephen Corman’s comment above, and his statement about the reduction in the prostate cancer mortality rate is correct (see below), it should be noted that, prior to the PSA era, the vast majority of men treated for prostate cancer were, in fact, never screened. At that time, in general, patients were diagnosed as a consequence of either an incidental finding of cancer while being surgically treated for BPH or the presence of symptoms of progressive prostate cancer (e.g., back pain). Widespread screening for prostate cancer simply didn’t happen prior to the 1990s.
In 1990, the US age-adjusted prostate cancer mortality rate was 38.6 per 100,000 (see Stewart et al.). For the 5-year period 2000-2004, it was 27.9 per 100,000 (see Cancer Facts and Figures 2008). This is a 27.7 percent reduction in the annual death rate over about 15 years. Actual mortality rates for the period 2005-2008 are not yet available.
Mike,
Precisely!
Stephen Corman’s point is elegantly simple and unassailable.
Coincidence of improved prevention and care is an unlikely explanation for the decline in deaths due to prostate cancer during the recent 18 years.
A 27.9 percent reduction rate in mortalities due to prostate cancer speaks for itself, and today scarcely anybody except for a few hardheads in high places maintain that widespread availability of an inferior PSA test is (largely) responsible for that decline.
Just think what might be accomplished in the battle against prostate cancer if better diagnostic tools were made available.
Phil Olsen