Lip cancer in Western Australia, 1982-2006: a 25-year retrospective epidemiological study

The aim of this study was to report on the epidemiological trends in incidence and mortality rates of lip cancer in Western Australia from 1982-2006. Incidence and mortality data were provided by the Western Australian Cancer Registry. Analysis of demographic distribution by gender, age, metro-rural residence and Indigenous status and by sub-site of lip cancer was undertaken. Percentages, crude, age-specific and direct age-standardized rates were computed with 95% confidence intervals. In Western Australia, lip cancer represents 49 per cent of all oral cancer cases. A total of 2152 new cases and 31 deaths due to lip cancer were reported. Eighty-one per cent of new cases occurred on the lower lip. The incidence rate ratio of males to females was 2.5-3:1, with non-Indigenous people suffering 98 per cent of lip cancer. Rural dwellers have higher standardized incidence rates when compared to people living in metropolitan areas. An increasing trend with older age is consistent throughout the study period. Over the 25 years, on average 90-100 people are diagnosed with lip cancer but only 1-2 people die each year. These mortality rates are very low indeed and are the reason for its good prognosis.