Cancer prevalence in United States, Nordic Countries, Italy, Australia, and France: an analysis of geographic variability.

BACKGROUND: The objectives of this study were to quantitatively assess the geographic heterogeneity of cancer prevalence in selected Western Countries and to explore the associations between its determinants. METHODS: For 20 cancer sites, 5-year cancer prevalence, incidence, and survival were observed and age standardised for the mid 2000s in the United States, Nordic European Countries, Italy, Australia, and France. RESULTS: In Italy, 5-year crude prevalence for all cancers was 1.9% in men and 1.7% in women, while it was ∼1.5% in all other countries and sexes. After adjustment for the different age distribution of the populations, cancer prevalence in the United States was higher (20% in men and 10% in women) than elsewhere. For all cancers combined, the geographic heterogeneities were limited, though relevant for specific cancers (e.g., prostate, showing >30% higher prevalence in the United States, or lung, showing >50% higher prevalence in USA women than in other countries). For all countries, the correlations between differences of prevalence and differences of incidence were >0.9, while prevalence and survival were less consistently correlated. CONCLUSION: Geographic differences and magnitude of crude cancer prevalence were more strongly associated with incidence rates, influenced by population ageing, than with survival rates. These estimates will be helpful in allocating appropriate resources.

Net survival: comparison between relative and cause-specific survival estimates.

This paper presents a comparison between cause-specific survival and relative survival calculated according to the Hakulinen method. The data are from the Tuscany Cancer Registry and we analysed the following cancer sites: stomach, colon, rectum, cervix and corpus uteri, female breast and skin melanoma. When cause-specific survival was calculated including among the deceased only those subjects whose death certificate reported strictly the same neoplasm as cause of death (three digits ICD-9), very good agreement between the two methods was found for stomach, lung, and skin melanoma and a good agreement was found for female breast. For cancer of the colon and rectum, in order to obtain similar estimates, deaths coded as caused by cancer in other sites of the large bowel and partially the not specified intestine had to be included. For cancer of the cervix and corpus uteri, in order to obtain similar estimates, but with cause-specific remaining higher than the relative estimates, deaths coded as not specified uteri cancer had to be included. In conclusion, cause-specific survival may be used also with overall mortality data, providing the death causes by cancers most susceptible to misclassification are to be included. However, using cause-specific survival creates some difficulties in comparative studies due to the different reliability of mortality data and to the different criteria used to identify the main cause of death.