In Memoriam: Pelayo Correa (1927-2024)

Pelayo Correa, born in Sonsón, Antioquia, in 1927, was one of the most influential figures in cancer epidemiology and pathology in Latin America and worldwide. His work transformed the understanding of gastric carcinogenesis and gave rise to one of the most solid and long-standing population-based registries on the continent. His scientific life —defined by rigor, curiosity, and public service— leaves an enduring legacy for generations of researchers.

Professor Correa graduated as a physician from the Universidad de Antioquia in 1949, where he completed his thesis on cancer statistics in the department —pioneering work that sparked his lifelong interest in differences in cancer risk across populations. This early study took him to Emory University in the United States, where he trained as a pathologist and solidified his etiologic vocation: to understand the causes of disease, not only its morphological expression. After completing his training, he returned to Colombia and joined the Universidad del Valle.

During a 1961 congress, his presentation on cancer patterns in Cali drew the attention of Dr. Harold Stewart of the National Cancer Institute (NCI), who shared the data with Dr. William Haenszel. From that exchange, Dr. Haenszel traveled to Cali and, together with Professor Correa, helped establish the Cali Population-Based Cancer Registry (RPCC), the first in Latin America and today one of the oldest in the world. Dr. Haenszel also served as his mentor in epidemiology, contributing to the design and conduct of the investigations that followed in subsequent decades, aimed at clarifying the determinants of gastric cancer.

The strength of the Cali Registry became evident early on. The RPCC publication in the Journal of the National Cancer Institute in April 1966 coincided with the release of the first volume of Cancer Incidence in Five Continents (January 1966), which included RPCC data. This convergence placed the Cali registry within the foundational landmarks of global cancer surveillance. At a time when the world was beginning to standardize comparative incidence measurement, Professor Correa's work provided rigorous data from Latin America, demonstrating that his epidemiological vision was not only aligned with global developments but contributed to them from the outset.

A central component of Professor Correa's scientific work was the Program Project continuously funded by the NCI—part of the U.S. National Institutes of Health—for more than forty years, one of the longest-standing grants ever awarded by the agency. Through this program, multiple complementary research lines were integrated: systematic follow-up of population cohorts, carefully designed longitudinal studies, and a clinical trial aimed at intervening in the natural history of precursor lesions of gastric cancer. Over the years, these long-term efforts enabled the clear delineation of the sequence of histological transformations now known as the "Correa cascade," a discovery that transformed understanding of gastric carcinogenesis and paved the way for contemporary studies on Helicobacter pylori, chronic inflammation, and tumor progression.

The execution of this program in Colombia was possible thanks to the operational capacity of the RPCC at the Universidad del Valle, whose stable structure, coordination with health services, and institutional credibility enabled long-term follow-up and the completion of the clinical trial with exceptional quality. This sustained collaboration between a Latin American population-based registry, and a U.S. research center not only produced fundamental scientific advances but also reflected the essence of Professor Correa's approach to research: methodological rigor, etiologic vision, and commitment to high-impact public health questions.

Beyond his pioneering role in population-based registries and etiologic research, Professor Correa played a leading role in consolidating global cancer surveillance. He served on the Editorial Committee of Cancer Incidence in Five Continents ¹, Volume III (1976), an honor reserved for experts with exceptional mastery of registry methodology. His international leadership was also reflected in his role as Founding Editor-in-Chief of Cancer Epidemiology, Biomarkers & Prevention (1990-1997), a journal that, under his direction, became a global reference in cancer epidemiology. In 1995, he was named an Honorary Member of the International Association of Cancer Registries, further affirming his global leadership.

Professor Correa's international prestige and the strength of his scientific work led him to positions of decisive influence in U.S. cancer science policy. He served for a decade on the NCI Board of Scientific Counselors (1982-1992), and later on the National Cancer Advisory Board (1992-1998), a presidential appointment and one of the NCI's most influential advisory bodies. That same year, he served on the Presidential Cancer Panel's Special Commission on Breast Cancer, helping to guide national priorities for prevention and control.

True to his identity as an etiologist, Professor Correa emphasized that the strength of a population-based registry depended on essential yet straightforward principles: counting only new cases, precisely defining the reference population, delimiting a specific territory, and verifying that each case corresponded to a resident of the registry area at the time of diagnosis. This conceptual discipline—learned and refined alongside Haenszel—explains why the RPCC not only endured for decades but also became an international model: it was born of the conviction that epidemiology exists to answer the question 'why' disease occurs and to guide public health action.

Professor Correa was also a generous mentor. His influence reached dozens of Latin American researchers, including the four authors of this obituary: Dr. Nubia Muñoz, who, as a student, found in the RPCC and in Professor Correa an early window into the world of research. Their careers, later intertwined in cancer epidemiology and in global projects of the International Agency for Research on Cancer, testify to a scientific tradition he helped sow. Among his disciples is also Luis Eduardo Bravo, who led the RPCC for more than 20 years and, along with Drs. María Blanca Piazuelo and María Constanza Camargo collaborated in the many studies led by Professor Correa.

Professor Correa's career in the United States—first at Louisiana State University and later at Vanderbilt University—was marked by extraordinary productivity. His 1975 Lancet article describing the "Correa cascade" permanently changed the understanding of gastric cancer and opened the way for subsequent research on Helicobacter pylori, carcinogenesis, and prevention. Even in his later years, Professor Correa maintained a critical reflection on the direction of epidemiology: he worried about its drift toward excessive technicality, yet he remained confident in the power of curiosity as the driving force of scientific knowledge and as a compass for future generations.

Figure 1. Dr. Pelayo Correa in the Pathology Laboratory at Vanderbilt University, Nashville, TN, in 2016. Courtesy of Blanca Piazuelo.

In recognition of this exceptional trajectory, we propose that Universidad del Valle consider designating the RPCC as the "Pelayo Correa" Population-Based Cancer Registry —an appropriate tribute to the scientist who founded it and to the enduring impact of his work on cancer epidemiology in Colombia and worldwide.

Today, we honor an eminent researcher, an exemplary mentor, and a human being deeply committed to public health. His legacy will endure in every RPCC analysis, in every study on gastric cancer, and in every student who discovers in epidemiology the same passion he found.