Key Programs

About Prostate, Lung, Colorectal & Ovarian Cancer Screening Trial (PLCO)

Main Objective

To evaluate the ability of screening tests to reduce deaths from four common cancers: prostate, lung, colorectal, and ovarian.

Accrual Period

September 1992 - July 2001

Participants

154,938 healthy men and women aged 55 to 74 at the time of enrollment.

Intervention

Participants were randomly assigned to one of two groups, the intervention group or the control group.

The intervention group received:

• PSA (men only), at initial visit and annually for 5 years
• Digital rectal exam (men only), at initial visit and annually for 3 years
• Flexible sigmoidoscopy, at initial visit and after 5 years in study
• Chest X-ray: smokers had test at entry and annually for 3 years. Never smokers had the test at entry and annually for 2 years.
• CA-125 blood test (women only), at initial visit and annually for 5 years
• Transvaginal ultrasound (women only), at initial visit and annually for 3 years

Control group receives usual care.

Data Collection Instruments

The Baseline Questionnaire, completed at the time of enrollment, collected information on demographics, personal and family history, lifestyle habits (including smoking) and history of screening for prostate, lung, colorectal and ovarian cancer.

The Annual Study Update questionnaire is mailed to all participants yearly for at least 13 years to identify cancers of the prostate, lung, colorectum, and ovary, as well as all deaths, that occur among both screened and control subjects during the trial.

Dietary questionnaires to look at relationships between diet and cancer were administered to all participants. Participants in the screened arm were asked to complete two full-length questionnaires, while those in the control arm were asked to complete one questionnaire.

A risk factor questionnaire was mailed in 2006.

Criteria for Participation

• General good health
• Ages 55 to 74
• Men and women
• No cancer of the prostate, lungs, colon, rectum, or ovaries

Total Sites

10 in the United States

Additional Study Objectives

• Assess other screening variables for each of the intervention tests including sensitivity, specificity, and positive predictive value.
• Investigate the potential of new early markers for use in cancer detection and molecular genetic epidemiology in cancer development through a biospecimen repository.

The PLCO protocol outline is available on NCI's PDQ.

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