Similar differences were found between the nicotinamide group and the placebo group with respect to new basal-cell carcinomas ( 20 % [ 95 % CI , -6 to 39 ] lower rate with nicotinamide , P = 0.12 ) and new squamous-cell carcinomas ( 30 % [ 95 % CI , 0 to 51 ] lower rate , P = 0.05 ) .