1. Descriptive Studies and Health Planning Unit, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan
2. National Institute for Cancer Research of Genoa, Genoa, and Alleanza Contro il Cancro, Rome
3. Epidemiology and Biostatistics Unit of the National Institute for Cancer Research of Genoa and Department of Oncology, Biology and Genetics of the University of Genoa, Genoa
4. Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy