Cancer incidence among indigenous adults in Brazil: A 19-year analysis of hospital cancer registry data (2000–2018).

Abstract

e13830 Background: Cancer disparities persist among Indigenous populations due to socio-demographic, cultural, and environmental factors. In Brazil, limited healthcare access contributes to late diagnoses and worse outcomes. While cancer trends have been extensively studied in the general population, evidence on Indigenous adults remains scarce. This study evaluates temporal trends in cancer incidence among Indigenous adults in Brazil from 2000 to 2018, using data from the Brazilian Hospital-based Cancer Registry (HbCR), and compares findings with estimates from the Brazilian Demographic Census. Methods: A retrospective cohort study was conducted using HbCR (SIS-RHC) data. The cohort included Indigenous individuals aged ≥18 years, diagnosed with malignant neoplasms (ICD-10), and treated within the Brazilian Unified Health System (SUS). Temporal trends in cancer incidence were assessed using the Mann-Kendall test, with bivariate analyses evaluating associations between variables. Cumulative incidence rates (CIR) were calculated based on the Brazilian Demographic Census of 2000 and 2010. Results: Among 3,701 Indigenous individuals (mean age: 56.91 years, SD: 16.22), 58.61% were female, 51.44% had elementary education, and 32.14% resided in the Northeast. Family history of cancer was reported by 35.22%; 62.19% did not consume alcohol, and 53% were non-smokers. Multiple primary tumors were absent in 96.93% of cases. The most common cancers were cervical (19.02%) and breast (11.51%), followed by non-melanoma skin (10.81%) and prostate (8.46%) cancer. Most cases were localized (stages I–II, 35.38%), while 33.71% were regional (stage III) and 30.92% metastatic (stage IV). Diagnoses at localized and regional stages (I–III) increased significantly (p < 0.001). Significant differences were observed across sexes and age groups (p < 0.001). Annual cancer case counts rose significantly from 2000 to 2018 (S = 113; p < 0.001), with 337 cases (8.84%) reported from 2000–2004, 982 (26.53%) from 2005–2009, 849 (22.94%) from 2010–2014, and 1,238 (33.45%) from 2015–2018. Overall, cases increased by 378.59% during the study period. The CIR calculated for the period, were as follows: 2000 to 2009: 169.59 cases/100,000 Indigenous individuals; and 2010 to 2018: 188.05 cases/100,000 Indigenous individuals. Conclusions: Cancer incidence among Indigenous adults in Brazil increased substantially from 2000 to 2018, with cervical and breast cancers being the most prevalent. Despite improvements in early detection, a significant proportion of cases remain diagnosed at advanced stages. These findings highlight the need for targeted public health efforts to improve screening, early diagnosis, and access to culturally tailored cancer care. This study provides critical insights to inform future cancer prevention and control efforts tailored to Indigenous populations in Brazil.