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

55 Years
74 Years
Open (Enrolling)
Colon Cancer, Rectal Cancer

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Trial Information

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


I. To determine whether screening with flexible sigmoidoscopy (60-cm sigmoidoscope) can
reduce mortality from colorectal cancer in women and men aged 55-74 at study entry.


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 (Colorectal Screening): Participants undergo a colorectal examination with a flexible
sigmoidoscope at baseline and year 5. 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 colorectal cancer (follow-up diagnostic procedures are through
their own medical care environment). Participants diagnosed with colorectal 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 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 colorectal 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.

Inclusion Criteria

Exclusion Criteria:

- Men and women who at the time of randomization are less than 55 or greater than or
equal to 75 years of age

- Individuals undergoing treatment for cancer at this time, excluding basal-cell and
squamous-cell skin cancer

- Individuals with known prior cancer of the colon, rectum, lung, prostate

- This includes primary or metastatic PLCO cancers

- Individuals with previous surgical removal of the entire colon, one lung, or the
entire prostate (men only)

- Until October 1996, women with previous surgical removal of both ovaries were
excluded from the trial. In order to increase the enrollment of women into the
trial, beginning in October 1996, these women were no longer excluded for this

- Individuals who are participating in another cancer screening or cancer primary
prevention trial

- Males who have taken Proscar/Propecia/finasteride in the past 6 months

- NOTE: Individuals who are already enrolled in the trial when their physician
prescribes finasteride are not prevented from taking this medication. As a
result, these participants will continue to be screened and followed just as
those participants who are not on finasteride.

- NOTE: Men who are taking Tamoxifen are not excluded from any part of the PLCO
Screening Trial.

- Prior to April 1, 1999 women were excluded from the trial if they were currently
taking or had taken Tamoxifen or Evista\Raloxifene in the past 6 months. As of
April 1999 based on a decision from the PLCO Ovary Subcommittee, women who have
or are currently taking Tamoxifen or Evista\Raloxifene are not excluded from

- Individuals who are unwilling or unable to sign the informed consent form

- Males who have had more than one PSA blood test in the past three years

- Individuals who have had a colonoscopy, sigmoidoscopy, or barium enema in the past
three years

Type of Study:


Study Design:

Allocation: Randomized, Endpoint Classification: Safety/Efficacy Study, Intervention Model: Parallel Assignment, Masking: Single Blind (Investigator), Primary Purpose: Screening

Outcome Measure:

Colorectal cancer-specific mortality rate

Outcome Description:

Event rates defined as the ratio of the number of events (deaths) to the person-years at the risk for the event.

Outcome Time Frame:

Up to 13 years

Safety Issue:


Principal Investigator

Christine Berg

Investigator Role:

Principal Investigator

Investigator Affiliation:

Mark O Hatfield-Warren Grant Magnuson Clinical Center


United States: Institutional Review Board

Study ID:




Start Date:

November 1993

Completion Date:

Related Keywords:

  • Colon Cancer
  • Rectal Cancer
  • Colonic Neoplasms
  • Rectal Neoplasms



Mark O Hatfield-Warren Grant Magnuson Clinical Center Bethesda, Maryland  20892