WHAT CAUSES BASAL-CELL CARCINOMA TO BE THE COMMONEST CANCER

We conducted a hospital-based case-control study in Brisbane, Queensla nd, to investigate the specific determinants of basal cell carcinoma ( BCC), as distinct from squamous cell carcinoma (SCC), with emphasis on ancestry, residential history, pigmentary characteristics, sun sensit ivity ad other constitutional factors. The sample was recruited from a dermatology outpatient clinic during an eight-week period in 1991, an d comprised 51 incident or recently diagnosed cases of BCC, and 112 ra ndomly selected controls with no known history of BCC or SCC. Twenty-s ix cases with both BCC and SCC were analysed separately. We found no r isk factor specific to BCC which might explain its extremely high prev alence. The strongest risk factors for BCC were advanced age, male sex and a propensity to freckle (independent of skin colour and tendency to bunt), all of which have previously been observed for SCC. A findin g not previously reported was an apparent protective effect Of increas ing body mass, specific to BCC alone.