e22564 Background: Cancer incidence among young adults (YA, 20–49 years) is rising globally. Information on risk factors and epidemiological behavior in this population is scarce, particularly in Latin America. Understanding temporal trends in YA may help explain underlying drivers of cancer increases and guide targeted public health strategies. Methods: We conducted a retrospective study including all patients with confirmed cancer (excluding non-melanoma skin cancer) at a tertiary center in Brazil from 2005 to 2024. Patients were stratified into YA (20–49 years) and late-onset cancer (LOC, ≥50 years). Annual incidence trends for the 10 most frequent YA cancers were analyzed using linear regression, calculating Average Annual Percent Change (AAPC). Clinical and sociodemographic variables at diagnosis (stage, diabetes, smoking, alcohol use, BMI ≥30, education, race) were analyzed using logistic regression. Results: Among 28,630 cases, 7,045 (24.5%) occurred in young adults (YA). Overall cancer incidence increased significantly in YA (AAPC 2.5%, p = 0.003) and in late-onset cancer patients (AAPC 3.85%, p < 0.001). The ten most frequent cancers in YA were breast, lymphoma, head and neck (CCP), cervix, colon, thyroid, brain, leukemia, melanoma, and ovary. Considering annual percent increases, the largest AAPCs were observed for cervical cancer (5.6%), colon (4.21%), lymphoma (3.23%), melanoma (2.73%), thyroid (2.71%), and breast (1.11%). Analysis of clinical and sociodemographic variables in YA revealed significant temporal increases in advanced-stage cases (stage III–IV) for breast (OR 1.06, 95% CI 1.03–1.09), lymphoma (OR 1.19, 95% CI 1.13–1.26), head and neck (CCP, OR 1.29, 95% CI 1.21–1.38), cervix (OR 1.22, 95% CI 1.15–1.30), colon (OR 1.20, 95% CI 1.13–1.28), brain (OR 1.32, 95% CI 1.09–1.60), and melanoma (OR 1.55, 95% CI 1.13–2.12). Pardo/Black race significantly increased in breast (OR 1.03, 95% CI 1.00–1.06), lymphoma (OR 1.04, 95% CI 1.01–1.07), cervix (OR 1.07, 95% CI 1.02–1.13), and colon (OR 1.09, 95% CI 1.04–1.15). Obesity (BMI ≥30) decreased in colon cancer (OR 0.77, 95% CI 0.66–0.90). Conclusions: Cancer incidence is rising among young adults in Brazil, with more advanced-stage diagnoses and higher representation among Pardo/Black individuals. These findings highlight the importance of tailored public health strategies, early detection, and further research to reduce disparities and improve outcomes.
Silva et al. (Thu,) studied this question.