ERBB2 and breast cancer: In the present article we, therefore, demonstrate the application of the CEAC, CEAFC and CERAC using a hypothetical example, and a real-world example based on a published Markov model evaluating the cost-effectiveness of palbociclib in addition to letrozole versus letrozole alone for the treatment of oestrogen-receptor positive, HER-2 negative, advanced breast cancer [17].