Aims and background: The MIAMOD method has been widely applied to derive regional and national cancer burden estimates. The method is based on a back-calculation approach using cancer-specific mortality and relative survival to derive expected incident and prevalent cases. Multiple tumors occurring in the same site for the same person (for example colon-colon) can be estimated just once. This has little effect on cancer-specific estimates, whereas it limits all cancers-combined estimates, where only cancer cases, rather than cancer diagnoses, can be accounted for by the method. The aim of this article is to present a specific strategy of application of the MIAMOD method to all cancers sites, which better approximates an estimate of 'cancer diagnoses'.
Methods: The strategy consists of breaking down the estimation process in separate applications to the most frequent cancer sites and to a 'remainder-site', given by all malignant sites except the previous ones. The separate estimates are then summed up to derive the overall quantities for all cancers combined. Cancer-specific mortality in the years 1985-2004 in the Tuscany cancer registry area (about 1,200,000 inhabitants) and relative survival data in the same area and periods (end of follow-up, 31 December 2006) were used to produce the estimates, which were then tested using observed incidence data in the same area and period.
Results: The standard application of the MIAMOD method underestimates all cancer incidence for both sexes. The mean relative difference between observed and expected incident cases is -14.8% for males and -17.2% for females. With the alternative method, the same mean relative difference drops to -8.2% for males and -6.1% for females.
Conclusions: The study provides a strategy to reduce a structural limit of the MIAMOD method in estimating the total burden of cancer disease.