Analyses of the geographical variation of cancer death certification between the 95 Italian provinces based on published data for the early 1970s showed substantial variations in mortality, higher rates being generally registered in northern areas, and marked gradients for most common neoplasms (Cislaghi et al. 1978). Originally, it was suspected that this pattern might have been influenced by under-certification of cancer deaths in southern regions. However, subsequent checks both of internal (e. g., between various age groups) and external (e. g., between death certification and cancer registration data) data reliability (Zanetti et al. 1982) showed a satisfactory degree of reliability of Italian cancer death certification, with the exception of a few selected problem areas of diagnosis and certification (i. e., cancers of liver, prostate, and brain, and the distinctions between colon and rectum or corpus and cervix uteri), which are probably also found in data from most other developed countries.KeywordsEsophageal CancerCancer MortalitySatisfactory DegreeCervix UterusSkin MelanomaThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.