Mean plasma 4-OHT was 0.2 and 1.1 ng/mL in 4-OHT and oral groups , respectively ( P = 0.0003 ) , whereas mean breast adipose tissue concentrations of 4-OHT were 5.8 ng/g in the 4-OHT group and 5.4 ng/g in the oral group ( P = 0.88 ) .