ABSTRACT
Introduction 47 Systems of classification 47 Changes in diagnostic technologies 48 Cancer registration 48 International variation 49 Variations with age and sex 52 Current issues in the descriptive epidemiology of lymphoid 54
neoplasms
Temporal trends: is non-Hodgkin lymphoma increasing? 54 Geographic variation: B cell versus T cell lymphoma 55 Changing diagnostics 56 Key points 57 References 57
Classic descriptive epidemiology is concerned with the occurrence of disease in human populations in terms of the characteristics of person, place and time.1 Of particular concern here are differences with age and between the sexes, as well as variations in the geographic distribution and trends over extended periods of time.
