Larynx cancer in Slovakia and the role of anatomical subsites

During the time period 1968-92, 6958 laryngeal cancers (6602 in men and 356 in women) were diagnosed in Slovakia and notified to the National Cancer Registry. We analysed long-term trends in incidence, mortality and survival. Mortality and incidence rates in Slovakian men rose rapidly until 1980 and more slowly subsequently. The mortality-to-incidence ratio initially was 40% and increased to 70% in the period 1985-88. A log-linear model showed that the more recent generations experienced the slowest increase in incidence. Incidence and mortality rates in women remained stable and did not exceed 1 per 100 000. The 5-year survival probability from invasive larynx cancer was 47%. Survival rates had shown no particular trend by year and age at diagnosis. The main finding was that 5-year survival from supraglottis cancer is 20% poorer than survival from glottis cancer. Supraglottis is the prevalent larynx subsite in countries with high larynx, oropharynx and oesophagus incidence rates. This supports the hypothesis that supraglottis cancer is more strongly linked to a synergistic effect of smoking and alcohol than glottis cancer.