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

The Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial was a large randomized controlled trial designed and sponsored by the National Cancer Institute (NCI). The goal was to determine the effects of screening on cancer-related mortality and secondary endpoints in men and women aged 55 to 74.

• Prostate: After 13 years of follow-up, there was no evidence of a mortality benefit for organized annual screening compared with opportunistic screening, which forms part of usual care.
• Lung: Annual screening with chest radiographs over a 4-year period did not significantly decrease lung cancer mortality compared with usual care.
• Colorectal: Screening with flexible sigmoidoscopy was associated with a significant decrease in colorectal-cancer incidence (in both the distal and proximal colon) and mortality (distal colon only)
• Ovarian: Among women in the general U.S. population, simultaneous screening with CA-125 and transvaginal ultrasound compared with usual care did not reduce ovarian cancer mortality.

The results of the trial influenced U.S. Preventative Services Task Force guidelines. Data generated by the study continue to be used to answer related crucial questions.

Cancer Data Access System (CDAS)

Additional information about PLCO can be found on the Cancer Data Access System (CDAS) website, including a trial summary.

CDAS also serves as a portal for PLCO datasets, including:

• Study data for screening, diagnosis, treatment, and mortality analyses for prostate, lung, colorectal, and ovarian cancers;
• Study data for incidence and mortality analyses for cancers of 14 other common sites of interest;
• Questionnaires;
• Lab results;
• Additional data from ancillary studies;
• Chest x-ray and pathology images; and
• Biospecimens.

Etiologic and Early Marker Studies (EEMS)

Over the course of the PLCO trial, over 2.9 million biospecimens were collected, including blood samples, buccal cells, and tumor tissue cores and microarrays. Biospecimens are available to qualified researchers through the Etiologic and Early Marker Studies (EEMS) program. Details of the review process and application materials are available on CDAS.

PLCO Atlas

The cohort of PLCO participants has been followed for more than two decades, resulting in a rich collection of anthropometric, lifestyle, and disease information, and includes data from several smaller-scale molecular studies. The NCI Division of Cancer Epidemiology and Genetics has genotyped 110,000 PLCO participants and developed PLCO Atlas as a resource for genetic studies.