Trial Information

Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial

PRIMARY OBJECTIVES:

I. To determine whether screening with chest x-ray can reduce mortality from lung cancer in
women and men aged 55-74 at entry.

SECONDARY OBJECTIVES:

I. To assess screening variables, other than mortality, for each of the interventions
including sensitivity, specificity, and positive predictive value.

II. To assess the incidence, stage, and survival of cancer cases. III. To investigate the
mortality predictive value of biologic and/or prognostic characterizations of tumor tissue
as intermediate endpoints.

IV. To conduct biomolecular and genetic research into factors associated with cancer
carcinogenesis and promotion, as well as the early detection of these factors.

OUTLINE: Participants in the overall PLCO study are stratified by screening center, gender,
and age (55-59 vs 60-64 vs 65-69 vs 70-74). Participants are randomized to 1 of 2 arms
(control vs screening).

ARM I (Control): Participants receive standard medical care. Participants complete a Diet
History Questionnaire (DHQ) at baseline.

ARM II (Lung Screening): Participants undergo a chest x-ray (one postero-anterior view) at
baseline and annually for 2 years. Participants classified as "smokers" undergo an
additional chest x-ray at year 3. A scheduling and tracking procedure is implemented to
ensure regular attendance at repeat screens for participants screened negative or for those
who are designated suspicious or positive at screening but for whom subsequent diagnostic
procedures do not reveal lung cancer (follow-up diagnostic procedures are through their own
medical care environment). Participants diagnosed with lung cancer via a screening test are
referred for treatment in accordance with current accepted practice for appropriate stage of
disease, patient age, and medical condition; a procedure is provided for contact with
qualified medical personnel to insure appropriate therapy.

Participants complete a Baseline Questionnaire (BQF/M) to assess smoking status.
Participants complete a Dietary Questionnaire (DQX) at baseline and DHQ at year 3. An Annual
Study Update (ADU) (previously referred to as the Periodic Survey of Health [PSH]
questionnaire) is mailed to each participant annually for 13 years to identify all prevalent
and incident lung cancers as all deaths that occur among both screened and control subjects
during the trial.

After completion of screening, participants are followed up for at least 13 years.