Between 1993 (when it was started) and 2001 (when it was closed to enrollment), the Prostate, Lung, Colorectal and Ovarian (PCLO) cancer screening trial enrolled nearly 155,000 men and women of 55 to 74 years of age. Half of them (the “intervention” arm) undergo regular cancer screening; the other half (the “control” arm) just carry on with their normal health care routine.
One of the primary goals of this trial is to determine whether screening for prostate cancer with a digital rectal exam (DRE) and a prostate specific antigen (PSA) test leads to a reduction in deaths from prostate cancer. A total of 38,350 men are enrolled in the prostate cancer intervention arm. Other similar goals address the other three cancers under study.
The active screening element of the study was completed in 2006. Additional follow up will continue until 2014 to determine the benefits (or harms) of the screening processes that are being studied. Thus, we do not expect to see the results of this study until perhaps 2015.
The following interim results have already been published with respect to prostate cancer:
7.5 percent of the participants in the intervention arm had a positive DRE and 7.9 percent had a positive PSA (defined in this study as a PSA level >4.0 ng/mL).
Of these men, 74 percent had a further diagnostic evaluation, and 31.5 percent had a prostate biopsy within 1 year of the positive screening test.
556 out of 4,801 men who showed suspicious screening results (11.6 percent) were diagnosed with prostate cancer within 1 year of the positive screening test
83 percent of the men diagnosed with prostate cancer had early stage (localized) disease, with no indication of spread of the disease to the lymph nodes or other organs.
A summary of the currently available prostate cancer research results from the PCLO trial is available as a fact sheet from the National Cancer Institute web site.