The relationship between basal and squamous cell skin cancer and smoking related cancers

BACKGROUND: We compared the risk of being diagnosed with smoking-related cancers (lung, oral cavity, upper digestive and respiratory organs, bladder, kidney, anogenital cancers and myeloid leukaemia) among people with squamous cell carcinoma (SCC) or basal cell carcinoma of the skin (BCC), with risks found in the general population using data from an Australian population-based cancer registry. METHODS: People diagnosed with BCC or SCC in 1980-2003 reported to the Tasmanian Cancer Registry, Australia, were followed-up by linkage within the registry, until diagnosis of a subsequent smoking-related cancer, death, or until 31 December 2003. Risk of developing a future smoking-related cancer was assessed using age Standardised Incidence Ratios (SIR). RESULTS: People diagnosed with SCC had an increased risk of lung cancer (men: SIR = 1.89, 95% confidence interval: 1.61-2.21; women: SIR = 2.04, 1.42-2.83) and all other smoking-related cancers (men: SIR = 1.38, 1.19-1.60; women: SIR = 1.78, 1.34-2.33). Men with BCC had a significant increased risk of lung cancer (SIR = 1.26, 1.10-1.44) but not of any of the other smoking-related cancers (SIR = 1.09, 0.97-1.23). CONCLUSIONS: Individuals with a history of SCC having an increased risk of developing smoking related cancers cancer suggests smoking as a common etiology. The relationship between BCC and smoking-related cancers is less certain.