<qa>  What should doxorubicin be reduced by 50?3.4 Cardiotoxicity In case of NCI grade II cardiotoxicity, doxorubicin should be reduced by 50. If cardiotoxicity is resolved, the dose may be carefully deescalated, 12,5 each time, in the subsequent courses. If severe NCI grade III cardiotoxicity develops, doxorubicin should be discontinued and should not be used again in the subsequent courses. 