MPIDR Working Paper
Economic progress as cancer risk factor. I: Puzzling facts of cancer epidemiology
MPIDR Working Paper WP-2005-021, 46 pages.
Rostock, Max-Planck-Institut für demografische Forschung (August 2005)
The increase in cancer burden in developed countries refers to three major causes: population aging, an increase in the cancer incidence rate, and an improvement in the survival of cancer patients. Among these reasons, only the increase in the cancer incidence rate is a negative factor that could be really managed to decrease cancer burden; it, thus, urgently needs explanation and action to develop adequate cancer prophylactics. We have conducted a comparative analysis of cancer incidence and mortality rates in different countries of the world for different time periods. The typical age-trajectory of overall cancer incidence rate (for both sexes and all cancers combined) is characterized by a peak in early childhood, low risk in youth, increasing risk afterwards, and a leveling-out or even a decline in cancer risk for the oldest old. Patterns of age-specific cancer mortality resemble the incidence rate patterns; however, mortality is commonly lower and its curve shifts towards higher age. This shift could be due to a time lag between the age of cancer diagnosis and death from the disease. Analysis of time and place differences in the cancer incidence rate revealed that the overall cancer risk is higher in more developed regions as compared with less developed ones, and that until recently it increased over time along with economic progress. The proportions of separate cancer sites within the overall cancer morbidity differ between more and less developed regions, and their change over time is also linked to economic development. Surprisingly, cancer incidence and mortality rates exhibit different time trends. This divergence is most probably related to the substantial improvement in the survival of cancer patients observed in the last 50 years in developed countries. This improved survival has decreased cancer mortality but not its incidence, which has increased. This suggests that in developed countries cancer treatment has seen much more substantial progress than cancer prophylaxis, which has hardly seen positive results for the majority of human cancers (with a few exceptions). In our second paper we discuss possible explanations of the link between economic progress and the increase in the overall cancer risk.
Key words: cancer incidence rate, age-patterns, time trends, place differences, economic progress