Lip cancer in South Australia, 1977-1996.

Lip cancer (140 ICD-9, C00 ICD-10) is a form of oral cancer occurring at the junction between the oral cavity and the skin. Lip cancer has a distinctive global epidemiology that is notably different from cancer occurring at other intraoral sites. This study reviews and analyses the epidemiological data for lip cancer from the South Australian Central Cancer Registry between 1977 and 1996. During this 20-year period, 2716 cases of lip cancer (2095 male, 621 female) and 35 deaths from this disease (23 males, 12 females) were reported. The average age of diagnosis was 58.3 years in males and 66.0 years in females. Very high age-standardised incidence rates (over 15.0 per 100000 per annum in males and 4.0 per 100000 per annum in females) were found, giving the South Australian population amongst the highest incidence of lip cancer in the world. Also of considerable concern was the finding that, contrary to global trends, these rates showed a significant increase over the 20-year period in both sexes. Possible reasons for these findings are discussed.