People in the trial receive regular and careful medical attention, so some health problems may be found early. If the screening test being studied is found to be effective in reducing the chance of dying from that disease, some people in the trial are likely to benefit. Knowledge about the screening test may be used to help other people as well. The side effects and risks of screening tests may not be understood completely. The screening method being tested may not detect cancer early or decrease the person s chance of dying from the disease.
False positives occur when test results are read as abnormal, but no cancer is actually present.
False negatives occur when test results appear normal even though cancer is actually present. Participants may not be able to choose the screening approach they receive. Health insurance plans may not cover the costs of cancer screening trials. Informed consent means that people are given information about the trial to help them make a decision about whether to participate. They need to understand what is involved, including details about the screening approach, tests, and the possible risks and benefits before agreeing to take part in the trial.