This analysis shows that incidence does indeed increase significantly with dose, the difference between the slope of the regression line and zero being significant at the 1% level. Most centres do not report on the laterality of tumours. However, analysis of data from those centres that do report later- ality (Table 2 and Figure 2) shows no significant increase in the incidence of bilateral tumours with annual ambient UV dose, but a highly significant one in the case of unilateral tumours.
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