TIME TRENDS OF LUNG AND LARYNX CANCERS IN ITALY

During the period 1970-1989, age-adjusted mortality rates for lung can cer in Italy increased by more than 50%, while rates for larynx cancer in males decreased by approximately 13%. This study aims to interpret this difference, which seems to contradict the finding that cigarette smoking is a common major risk factor for both lung and larynx cancer . To this end, we jointly analyzed the time trends of incidence, survi val and mortality. We first examined survival data taken from the popu lation-based Lombardy Cancer Registry (northern Italy). Based on data referring to 880 incident cases of larynx cancer, diagnosed during the period 1976-1987, we estimated a 3% annual increase in relative survi val. By contrast, no significant period effect was observed for surviv al rates of 2,259 incident cases of lung cancer. National incidence ra tes were estimated using official mortality data and the above-describ ed survival data. Age-adjusted estimated incidence rates increased, fr om 1970 to 1989, for both cancer sites: +55% for male lung, +56% for f emale lung, cohort effect, which are diverging for mortality, are near ly parallel with regard to incidence. This analysis suggests that a su bstantial improvement in survival of larynx cancer patients may largel y explain the difference in mortality trends for cancer of lung and la rynx. (C) 1994 Wiley-Liss, Inc.