A study involving researchers from the Sant Pau Research Institute (IR Sant Pau) and the Universitat Autònoma de Barcelona, led by the University of Oxford, has analyzed trends in colorectal cancer in the United Kingdom between 2000 and 2021 using real-world primary care clinical databases. The research, published in The American Journal of Gastroenterology, has revealed a steady increase in early-onset colorectal cancer (in people under 50) over the past two decades.
According to the study, although the overall incidence of colorectal cancer has stabilized—thanks in part to screening programs introduced in 2006—there has been a noticeable rise among younger populations. “It’s not an explosion of cases in absolute numbers, but the concern is that this increase is sustained in an age group where this trend was not typically seen,” explains Dr. Patricia Pedregal, from the Digestive Pathology Research Group at IR Sant Pau and a specialist in the Digestive Diseases Department at Hospital Sant Pau, first author of the study.
The study is based on data from over 150,000 patients diagnosed in the U.K., with a total cohort exceeding 35 million people. “One of the strengths of this study is that by using real population-based databases, we’re not extrapolating estimates—we’re working with data directly recorded by primary care physicians,” adds Dr. Pedregal.
The analysis also proves that the implementation of screening programs has had a positive impact on older age groups, stabilizing or even reducing incidence among people aged 60 to 79, and slightly improving survival in that group. However, individuals under 50 are not included in these programs, which may partly explain the increase in that population.
“Stabilization in older adults confirms that screening works. But we need to start a conversation about whether we should begin earlier. It’s also essential for doctors and patients to be alert to warning signs—even in younger people,” emphasizes Dr. Pedregal.
Another key finding of the study is the limited improvement in survival rates over time, despite advances in treatments. Overall survival one year after diagnosis is 78%, but this drops to 51% at five years and 38% at ten years. “We would expect to see a clearer improvement with today’s treatments, but that’s not reflected in the data. This suggests that beyond treatment, there are structural and diagnostic factors we need to improve,” warns the researcher.
The study also confirms that the United Kingdom still has poorer colorectal cancer survival rates compared to other European countries with similar healthcare systems, although the reasons for this are not entirely clear.
One of the major methodological contributions of this study is the use of real-world data from primary care records rather than traditional cancer-specific registries. This allowed for a more representative cohort of the general population and a very extensive longitudinal follow-up—over two decades in some cases.
“Cancer registries are created for specific purposes, and many times estimates are used to calculate incidence and prevalence. In our case, all calculations come from an integrated database with real information from patients treated within the U.K. public health system. That gives our results greater robustness and validity,” notes Dr. Patricia Pedregal.
In addition, these databases make it possible to analyze large-scale epidemiological patterns without the need to individually recruit patients—something that would be virtually unfeasible in a traditional hospital setting. “Having a sample of over 35 million people and more than 20 years of data is a unique opportunity to understand the true evolution of colorectal cancer in the population. This information can help shape public health policies, optimize screening programs, and in the future, guide more personalized treatment strategies,” adds the researcher.
This approach also highlights the role of primary care not just as the first level of care, but as a key source of information for biomedical research. “These databases reflect the real activity of general practitioners and make it possible to generate evidence applicable to routine clinical practice. They are a powerful tool for advancing cancer research,” concludes Dr. Pedregal.
A Grant That Supports International Research
This research was made possible thanks to a two-month research stay by Dr. Patricia Pedregal at the University of Oxford, as part of her doctoral thesis. It was supported by a 2024 grant from the Fundació Privada for placements in biomedical research centers or leading hospitals.
During this stay, Dr. Pedregal joined the team at the University of Oxford’s Centre for Statistics in Medicine, which specializes in the analysis of real-world clinical data. This direct collaboration has already led to new scientific projects. Currently, two additional studies are underway: one using data from six European countries and another focused again on the U.K. There are also efforts to replicate this research using data from the Catalan healthcare system.
“This stay allowed me to learn firsthand how leading groups in clinical epidemiology and large database analysis work. It was a key experience in my development as a researcher and has opened up new collaboration opportunities that will undoubtedly impact future research lines in digestive health and cancer,” says Dr. Patricia Pedregal.
Reference Article
Pedregal-Pascual P, Guarner-Argente C, Tan EH, Golozar A, Duarte-Salles T, Rosen AW, Delmestri A, Man WY, Burn E, Prieto-Alhambra D, Newby D. Incidence and survival of colorectal cancer in the United Kingdom from 2000-2021: a population-based cohort study. Am J Gastroenterol 2025. https://doi.org/10.14309/ajg.0000000000003460
