The Prospective Dutch Colorectal Cancer (PLCRC) Cohort: Towards a unique patient-reported outcome enriched “real-world” data cohort

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Background: The initiation of high-quality pan-population cohort studies is a major research priority for the improvement of colorectal cancer (CRC) outcomes as advocated by regulators and the research community. In 2013, the PLCRC cohort of the Dutch Colorectal Cancer Group was initiated in which longitudinal clinical data and patient-reported outcomes (PRO) are collected, along with pathology data and biospecimens, to serve as an infrastructure for a broad body of observational and (randomized) interventional research. Here we report on the cohort’s progress and investigate whether it develops in the direction of a nation-wide cohort of “real-world” nature. Methods: Clinical and demographical data of PLCRC participants, as prospectively collected in the Netherlands Cancer Registry by qualified data managers, were compared with the total Dutch CRC population with incidence between 2013-2017 (ref. population) which was also obtained from the Netherlands Cancer Registry. Variable distributions are compared using t-tests and χ2-tests, whereas cohort characteristics are descriptive. Results: In June 2019, 5,746 patients were enrolled in 52 / 75 Dutch hospitals, and 81% consented to receive repeated PROs. Compared to patients enrolled between 2013-16 (N = 1,093, 1-17 recruiting hospitals), we found a small shift towards the Dutch ref. population (N = 74,692) for patients enrolled between 2017-19 (N = 4,653, 17-52 hospitals) in terms of age at diagnosis (mean 64.6±10.2 years in 2013-16, 65.2±10.8 in 2017-19, and 69.5±10.9 in the ref. group), sex (65% males in 2013-16, 61% in 2017-19, and 56% in the ref. population), location of primary tumor (56% rectum in 2013-16, 40% in 2017-19, and 31% in the ref. population) and TNM stage (35% stage I-II in 2013-16, 41% in 2017-19, and 48% in the population). Conclusions: Over the past years, the number of PLCRC recruiting centers and participating patients, with high consent rates for PROs, steeply increased. Further improvements in recruitment methodologies and multidisciplinary enrolment of patients will continue to enhance PLCRC’s representation of the “real-world” and its ability to supplement trial-based evidence.