Stemming colorectal cancer in Latin America

Little is known about colorectal cancer screening strategies throughout the Western Hemisphere, with the exception of the U.S. and Canada. In a recent study by Regenstrief Institute, Indiana University School of Medicine, University of Alabama at Birmingham, and University of North Carolina, Chapel Hill, researcher-clinicians are one of the first to identify and evaluate colorectal cancer screening programs in Latin America.

The research team made several significant findings, including the lack of screening programs in low-middle-income countries, such as Honduras, El Salvador, Guatemala, and Bolivia. The researchers also found the prevalence of colorectal cancer in high-middle-income countries, such as Brazil, Argentina, Uruguay, and Chile, to be similar to the prevalence in high-income countries.

Detection of colorectal cancer via screening enables either earlier diagnosis with a better prognosis or prevention from removal of pre-cancerous polyps for a disease that is the second leading cause of cancer-related deaths worldwide and typically does not have symptoms in its early stages. While globally, colorectal cancer disproportionately affects high-income countries, both incidence and deaths are increasing in low- and high-middle-income countries, which include most Latin American nations.

Although a complete picture of colorectal cancer in Latin America is not available due to the uncertain completeness of data collection from its cancer registries, its incidence is increasing. The study authors note limited resources and infrastructure as well as the absence of public awareness in much of the region. They emphasize the need throughout Latin America for more screening and call for research on prevention.

The research team reviewed and analyzed studies of cancer screening in Latin America written in English, Spanish, and Portuguese, which included a total of nearly 124,000 participants.

In addition to identifying a lack of screening programs in low-middle-income countries, the researchers found that colon cancer screening strategies employing either or both noninvasive fecal immunochemical tests (FIT), which look for blood in stool, or screening colonoscopies, had been successfully implemented in Brazil, Argentina, Mexico, Costa Rica, Uruguay, and Chile—all high-middle-income Latin American countries.

The researchers report these high-middle-income countries in Latin America had a high uptake (86 percent) of screening. Significantly, more than 75 percent of patients received a colonoscopy following positive results from stool testing in this subset of Latin American countries.

According to study senior author Regenstrief Institute Research Scientist Thomas Imperiale, M.D., these findings suggest that establishing population-level structured screening programs in Latin America, at least in high-middle-income countries, would potentially be as effective at reducing colorectal cancer-related disease burden as they are in other regions.

"I would expect that more organized cancer screening would have the same benefit for these countries as it has for the U.S., Canada, and European countries."

"FIT would be a good screening choice economically and logistically throughout Latin America. If countries are interested in cost-effectiveness, efficiency, and reach, FIT would appear to be the test of choice. Worldwide, it's the most commonly used screening test," he added.

Study first author Eleazar Montalvan-Sanchez, M.D., an internal medicine resident physician at IU School of Medicine, who is from Honduras, says the findings of this study are important for patients, physicians, and policymakers in the U.S., as well as in Latin America.

"Most of the patients who I see here in Indianapolis are immigrants from Latin America who speak little English. When I try to discuss colorectal cancer screening with them, it's something new, something they have not been exposed to, unlike, for example, the availability of COVID-19 vaccines."

"I recall a recent patient who immediately refused a colonoscopy but didn't give me any reason. When, at his next appointment, we discussed his refusal, he shared that he had said no because he had never heard about it [colorectal cancer screening] before. It's important for physicians in the U.S. to know about colon cancer screening in Latin America as we work to improve health outcomes for this population."

The authors concluded, "This systematic review and meta-analysis found both the substantial burden of colorectal neoplasia and the feasibility of organized screening programs in Latin America. It also highlights the need for more data on CRC [colorectal cancer] burden or screening feasibility in the Latin American LMICs [low-middle-income countries]."

"CRC incidence is rising in Latin America as fast as anywhere in the world, warranting effective preventive measures, particularly with cost-effective, FIT-based screening programs. CRC screening should become a greater research and public health priority in Latin America."

"Colorectal Cancer Screening Programs in Latin America" is published in JAMA Network Open.