The researchers will be in contact with the participants for at least 10 years from the time they enter the study. Participation is voluntary and participants may withdraw from the study at any time. The researchers will regularly monitor the information received from the participants and the tests conducted. If a benefit from a particular test is seen, that portion of the study may be stopped so the test can be made available to the general public. Also, if there is a health risk found from administering a test, that part of the study will be modified or stopped.
All medical procedures carry some risk.
All the potential risks from the exams will be fully explained, and are included in a written consent form that each participant signs before enrolling in the trial. The values of the digital rectal exam in screening for prostate cancer and the sigmoidoscopy exam in screening for colorectal cancer are not well documented. The PLCO Trial will provide vital information on whether use of these exams decreases the number of deaths caused by these cancers. Men and women who are interested in participating in the PLCO Trial should contact the center nearest to them. Locations of the centers can be found by contacting NCI's Cancer Information Service.