Cancer Mortality in Italy

Recent years have seen what could only be described as a renaissance in the field of Descriptive Epidemiology, the branch of science which deals with national and international variation of disease rates, time trends, spatial aggregation and the description of disease occurrence in groups with particular characteristics. This is particularly true for « cancer », with the recent publication of many fine examples of cancer atlases and compendia of time trends for national and sub-national levels. Much of this work has been inspired by the work of the editors of the five volumes of « Cancer Incidence in Five Continents » (2, 3, 6, 9, 10), which now provide cancer incidence statistics from the early 1960's until the early 1980's in an increasing number of regions of the world. Despite ·the arrival on the scene of cancer incidence statistics there undoubtedly remains an important place for mortality data, such as presented in the following paper (5), from a national population. Unfortunately, with few exceptions -(notably Nordic countries, Scotland, German Democratic Republic, New Zealand), very few countries currently have national cancer registration schemes, which exist generally on a regional basis and many of these are more recent in origin, thereby making. detailed examination of temporal trends impossible. The availability of long term trends provides an opportunity to examine data presented in such a way as to investigate variation in cancer occurrence by birth cohort and hence reduce the possible effect of biases produced by artefacts such as changing classifications and interpretation of coding rules (7, 8). Of course, mortality data are more approximate to incidence data for some forms of cancer than others. For lung cancer and oesophageal cancer, both highly fatal disease, these two will be nearly the same: For others, such as breast cancer where survival rates are fairly good, the approximation between incidence and mortality is less strong. For tumours such as testicular cancer . and Hodgkin's disease, where treatment is now extremely effective, mortality and incidence data are not congruent. For other forms of cancer there are diagnostic and classification problems to be taken into account. These include, for example, the difficulty involved in the separation of liver, brain and bone tumours into primary or ·secondary tumours; the great difficulty in diagnosing pancreatic cancer; the improved ascertainment for prostate and ovary; and changes in the classification of lymphomas (1). These points are worth bearing in mind when examining the material presented by La Vecchia and his colleagues (5). The authors provide a clear and comprehensive presentation of trends in cancer mortality in various sites in Italy between 1955 and 1984. The materials . highlight a number of important changes whieh are taking place in the Italian population. Principal of these is the continuing overall increase in lung cancer and in other tobacco-related neoplasms among Italian men with the hint of a . reduction of the rate of increase among successively younger generations. These figures, reflecting changing patterns of cigarette smoking among younger Italians, confirm (if any further confirmation is required) the carcinogenic hazard of cigarettes one of the very few products marketed which causes significant morbidity and · notable mortality among those who use the product as the manufacturer intended. This has led to the overall increase in cancer mortality among males while cancer rates in females have remained fairly constant over the period. Marked increases are apparent in cancers of the mouth and pharynx, larynx and oesophagus in males. These cancers, which share common risk with the joint effects of tobacco and alcohol consumption again highlight prospects for prevention: elimination of cigarette smoking and moderation of alcohol consumption could bring about substantial reductions in death rates from these cancers. The declines in bladder cancer beginning to become evident among younger males in Italy partly reflect changing cigarette smoking habits but also, in large part, reflect the changing (safer) working environment. The identification of occupational risk and the tightening of safety standards have been a feature of Italian public health for several decades and have certainly contributed to reducing levels of this most obviously occupation-related cancer site. The declines in stomach cancer, in both sexes, and the increases in colorectal cancer, again in both sexes, are almost certainly due to the changing Italian diet throughout this century. The exact components of the diet responsible for these changes, which macronutrients or micronutrients, are not yet clear and their identification should be an epidemiological priority. From the data presented in the following paper . (5), an interesting comparison can be made with stomach and lung cancer in Italy and the United States. There is, apparently,