Epidemiological Transition of Cancer: A Systematic Analysis From the Global Burden of Disease Study 2016

Abstract

Background: The epidemiologic transition describes the transition from high mortality due to infectious diseases to high mortality from NCDs as societies move up the socioeconomic ladder. Since some cancers have infectious etiologies, it is unclear how socioeconomic development impacts cancer burden. This knowledge, however, is crucial to inform health policies, and resource allocations. Aim: We analyzed the cancer transition between 1990 and 2016 using the Global Burden of Disease (GBD) 2016 cancer estimates. Methods: We used the GBD 2016 cancer estimates from 1990 to 2016 as well as the sociodemographic index (SDI). The SDI is a composite indicator of development including fertility, education, and income with a higher SDI representing improved socioeconomic development. To describe the cancer transition, we analyzed how cancer incidence, and mortality changed depending on the SDI with special emphasis on the most common cancers at the global level (lung, colorectal, breast cancer) as well as on common cancers with infectious etiologies (stomach, liver, cervical cancer). Findings: Within and across world regions, age-standardized total cancer incidence (ASIR) either remained stable or increased with SDI except for the regions at the highest level of SDI where ASIR either plateaued or has peaked. For most regions age-standardized total cancer mortality (ASMR) decreased with increasing SDI. For lung cancer, ASIR and ASMR increased across regions with improvements in development but have remained stable or decreased within regions with increased SDI. Colorectal cancer ASIR increased within and across regions with improvements in SDI, whereas ASMR increased with higher SDI within the least developed regions but declined with improvements in SDI for more developed regions. Breast cancer ASIR increased within and across regions and ASMR decreased within most regions with improvements in SDI. However, breast cancer ASMR showed large heterogeneity within regions of the same SDI level. Of the cancers with infectious etiologies, stomach, and cervical cancer ASIR and ASMR decreased with higher SDI within and across regions. However, for liver cancer, ASIR and ASMR by SDI varied substantially within and across regions without a clear pattern. Conclusion: The epidemiologic transition theory explains trends in incidence and mortality for certain cancers (cervical, stomach). However, even though for many cancers there is a clear pattern of changes in incidence and mortality with regards to development level, this pattern rarely supports the epidemiologic transition theory of decreases in cancers due to infectious etiologies and increases in cancers that have mainly been attributed to a “western lifestyle”. What is evident is a “fourth phase” of the epidemiologic transition where, for many cancers that are amenable to treatment, cancer mortality decreases with improvements in development despite stable or increasing incidence.