ABSTRACT
Background: National cancer registration reports provide huge potential for identifying patterns and trends of policy, research, prevention and treatment significance. Yet given the range of factors involved in cancer onset, case identification, progression and reporting, pin-pointing this complexity requires systematic thinking and varied strategies of data analysis. Methods: The study extracts data about incidence rates (IRs) and mortality rates (MRs) of lung, stomach, colorectal and liver cancers for 2004, 2006 and 2009 from relevant China National Cancer Registry (CNCR) reports and analyzes the data using line-graphs, ratios and logistic growth modeling. Results: The study shows that: a) all line graphs of age-specific IRs and MRs of the 4 cancers characterized typical S-shape with substantial differences in terms of smoothness, height and proximity; b) MR lines mimicked and located below the corresponding (of the same cancer, population group and year of reporting) IR lines for almost all the age groups except 1 to 2 oldest ones; c) colorectal cancer witnessed the lowest MR/IR ratios on average followed by gastric and lung cancers and all such ratios featured an increasing trend along the age spectrum; d) urban vs. rural ratios in IRs or MRs showed an increasing trend along the age axis for 3 out of the 4 cancers but a typical v-shaped curves for stomach cancer; e) the lines of recent vs. early ratios in cumulative IRs or MRs for urban areas located apparently closer than that for rural areas; f) all the age-specific IRs and MRs fitted very well with logistic growth models (goodness of fit> 0.91) and the integrations and ages when the models reached 5%, 50% or 95% of their highest values yielded interesting features. Conclusion: The study provides useful perspectives for analyzing age-specific IRs and MRs and reveals a number of interesting patterns and trends with cancer counts reported by CNCR.