Vitor Fiorin Vasconcellos, N D'agostini, Jonathan Grassi, Luiz Cláudio Barreto Silva Neto, Renan Pazini Borges, Leticia Batista de Azevedo, Raphael Manhães Pessanha, Etreo Junior Carneiro da Silva Minarini, Guilherme Augusto Loiola Passos, Gabriel Colombo Pereira, Lívia Machado Giacomin, Regina Aparecida Garcia de Lima, Liliana Vásquez Ponce, Luís Carlos Lopes‐Júnior
Background/Aims: The global incidence of early-onset (EO) cancers-defined as malignancies diagnosed in individuals under the age of 50-has increased significantly over recent decades, particularly in high-income countries. However, epidemiological data from Latin America remain fragmented and underexplored. This study protocol describes a scoping review designed to systematically map and synthesize the available evidence on EO cancer incidence trends in Latin American populations. Methods: The review will be conducted in accordance with the JBI Manual for Evidence Synthesis and reported following PRISMA-ScR guidelines. A comprehensive search will be performed across multiple databases (PubMed, Embase, Scopus, LILACS, Cochrane, Web of Science), clinical trial registries, and gray literature sources without language or date restrictions. Studies reporting incidence data on solid tumors diagnosed before age 50 in Latin American countries will be included. Study selection and data extraction will be performed independently by four reviewers using a standardized form. Data will be analyzed through descriptive statistics and qualitative synthesis. The findings aim to highlight incidence patterns by cancer type, population characteristics, and methodological approaches. Results: The final scoping review will present the search results, the study inclusion process, and the data analysis. Conclusion: This review will provide a consolidated epidemiological overview to inform public health policy, improve cancer surveillance, and identify research gaps in the region. Review Registration: This protocol was registered on the Open Science Framework (OSF). The registry number is OSF.IO/TZ67D. This registration ensures the transparency and credibility of our research process, as it provides a public record of our study design and methods.