Socioeconomic and Systemic-Level Determinants of Stage at Diagnosis in Colon and Rectal Cancer: A 30-Year Population-Based Study in Quito, Ecuador
Carol T. Albacura-Campues, Raul A. Ayala Davila, Monsermín Gualán, David Vera, Philip J. Cooper, Natalia Romero-Sandoval,Purpose
Health systems in middle-income countries are often compromised by parallel, unintegrated subsystems (public safety-net, social security, private care), exacerbating health disparities. We evaluated how this architecture and individual socioeconomic position relate to advanced clinical stage at diagnosis, stratified by anatomic site (colon and rectal) and age cohort, in Quito, Ecuador, over a 30-year period (1990-2019).
Methods
After excluding unstaged and death certificate-only cases, data from 2,552 patients were analyzed. Selection bias was evaluated using Cramer's V and rank-biserial effect sizes. Multivariable logistic regression identified factors associated with synchronous late-stage (stage IV) presentation, adjusting for demographics, socioeconomic markers, and diagnostic health sector. Secondary overall survival trends were evaluated using Kaplan-Meier estimates and exploratory stage-stratified Cox models.
RESULTS
In patients ≥65 years, public-sector diagnosis was associated with a higher odds of late-stage colon cancer (adjusted Odds Ratio = 2.04; 95% CI, 1.24 to 3.35) compared with diagnosis in the private sector but showed no association with rectal cancer. Late-stage diagnosis probability remained stable over the 30-year study period. Exploratory survival models linked public-sector entry to higher mortality hazards (adjusted hazard ratios, 1.35-3.01), with adjusted survival trajectories exhibiting broad temporal stability across recent decades.
CONCLUSION
Public-sector care s persistently associated with diagnostic delays that has spanned three decades, independent of socioeconomic position. Beyond early-detection barriers, exploratory survival models generate the hypothesis that public-sector disparities extend into longitudinal survival outcomes, reinforcing the urgent need for structural reforms such as organized screening and equitable public care pathways.