Objectives: To assess the incidence and multiplicity of keratinocyte cancers (basal cell carcinoma [BCC] and squamous cell carcinoma [SCC]) excised in Australia, and to examine variations by age, sex, state, and prior skin cancer history.
Design: Analysis of individual-level Medicare data for keratinocyte cancer treatments (identified by eight specific MBS item codes) during 2011–2014. Histological data from the QSkin prospective cohort study were analysed to estimate BCC and SCC incidence.
Setting: A 10% systematic random sample of all people registered with Medicare during 1997–2014.
Participants: People aged at least 20 years in 2011 who made at least one claim for any MBS medical service during 2011–2014 (1 704 193 individuals).
Main outcome measures: Age-standardised incidence rates (ASRs) and standardised incidence ratios (SIRs).
Results: The person-based incidence of keratinocyte cancer excisions in Australia was 1531 per 100 000 person-years; incidence increased with age, and was higher for men than women (SIR, 1.43; 95% CI, 1.42–1.45). Lesion-based incidence was 3154 per 100 000 person-years. The estimated ASRs for BCC and SCC were 770 per 100 000 and 270 per 100 000 person-years respectively. During 2011–2014, 3.9% of Australians had one keratinocyte cancer excised, 2.7% had more than one excised; 74% of skin cancers were excised from patients who had two or more lesions removed. Multiplicity was strongly correlated with age; most male patients over 70 were treated for multiple lesions. Keratinocyte cancer incidence was eight times as high among people with a prior history of excisions as among those without.
Conclusions: The incidence and multiplicity of keratinocyte cancer in Australia are very high, causing a large disease burden that has not previously been quantified.