The Colorectal Cancer Mortality-to-Incidence Ratio as a Potential Cancer Surveillance Measure in Asia


Visiting Researcher UC Irvine Medical Sciences, Irvine


Background: The cancer mortality-to-incidence ratio (MIR) has been established as an important measure of health disparities in local and global circumstances. Past work has corroborated a linkage between the colorectal cancer MIR and the World Health Organization (WHO) Health System ranking. The literature further documents many Asian countries having incomplete cancer registries and a lack of comprehensive colorectal cancer screening guidelines. Materials and Methods: The colorectal cancer MIR values for 23 Asian countries were calculated from data obtained from the 2012 GLOBOCAN database. The 2000 World Health Organization (WHO) Health System rankings were used as a proxy for health system infrastructure and responsiveness. A regression equation was calculated with the MIR as the dependent variable and the WHO Health System ranking as the independent variable. Predicted MIR values were next calculated based on the regression results. Actual MIR values that exceeded 0.20 from the predicted MIR were removed as 'divergent'points. The regression equation was then re-plotted. Goodness-of-fit for both regressions was assessed by the R-squared test. Results: Asian countries have a relatively wide colorectal cancer MIR range, from a minimum of 0.24 to a maximum of 0.86. For the full dataset, the adjusted R-squared value for this regression was 0.53. The equation was then used to calculate a predicted MIR, whereby two data points were identified as 'divergent' and removed. The adjusted R-squared for the edited dataset increased to 0.66. Conclusions: Asian countries have a marked range in their colorectal cancer MIR values and there is a strong correlationwith the WHO Health System ranking. These results corroborate the contribution of the MIR as a potentially robust tool in monitoring changes in colorectal cancer care for Asian nations.