Cancer Burden Estimates and Forecasts: Uses and Cautions

Incidence, prevalence and mortality indicators, as provided in this monographic issue for each of the Italian regions and for the major cancers (stomach, colorectal, lung, breast, uterine cervix, prostate cancer and skin melanoma), provide necessary information for cancer control activities. In Italy, these activities are mainly organized on a regional level.

Incidence depends on the distribution of risk factors in the population and is monitored to assess the efficacy of primary prevention programs as well as to measure the effect of screening activities. Mortality is a summary indicator incorporating the effects of both occurrence and survival. Finally, the prevalence of people with a diagnosis of cancer within a population is a direct measure of the demand for health care and social services. When taken separately, each of these indicators provides a partial view of the cancer phenomenon and should therefore be interpreted with caution. In this paper we give some examples of the uses of these indicators, and also of the interpretation difficulties by relating the regional cancer incidence to tobacco use, overweight and residence in polluted sites. We comment on the observed mortality trends in terms of their contribution to incidence and survival. We associate the estimated trends in cancer prevalence from 1990 to 2015 with the gross domestic product, an indicator of the resources available in Italy. The simultaneous consideration of all three indicators, as was done throughout this monograph by means of a unique methodology, is suggested for public health use.

Estimates of cancer burden in Liguria

Aims and background

The regional health care system of Liguria caters for a resident population which is among the oldest in Europe. One population-based cancer registry is present in the region, providing incidence and survival data for the Genoa province (covering 55% of the regional population). This paper will estimate the incidence, prevalence and mortality in the Liguria region for cancers of the lung, breast, prostate, colon-rectum, stomach and uterine cervix and melanoma of the skin in 1970—2015.

Methods

The estimated figures were obtained by applying the MIAMOD method. Starting from mortality and survival data, incidence and prevalence were derived using a statistical back-calculation approach. Survival was modeled on the basis of published data from the Italian cancer registries. The MIAMOD method was applied also to estimate the colorectal cancer incidence, mortality and prevalence rates in the Ligurian provinces in the period 1988—2015.

Results

In 2012 about 1,500 new cases of breast cancer were expected in Ligurian women. The estimates for the other cancer sites were considerably lower, ranging from 839 (colon-rectum) to 54 (cervix). In men about 1,400 new cases were estimated for prostate cancer, while the incidence for the other sites ranged from 1,118 (colon-rectum) to 208 (skin melanoma). The breast cancer prevalence rate was more than 10 times the incidence rate in women, and the lung cancer prevalence rate was more than double the incidence rate in both sexes. Mortality rates were highest for lung cancer in men and breast cancer in women; the lowest rates were estimated for melanoma and cancer of the uterine cervix.

Conclusion

In Liguria a large portion of the health expenditure has been devoted to diagnostic and therapeutic resources. This may have contributed to the reduction of mortality rates and to the improvement of cancer survival. This phenomenon, added to population aging, will inflate the cancer prevalence. One of the major challenges for the Liguria region is to face the increasing demand for oncology services.