EGFR and metastatic colorectal cancer: Entropy extracted from [18F]FDG PET/CT has recently been used for PFS prediction in patients with high-risk squamous cell carcinoma of the oropharynx after chemoradiation [30], and in patients with lung cancer after EGFR tyrosine kinase inhibitor treatment [31], and has also been found to be associated with failure to respond to third-line systemic treatment in metastatic colorectal cancer [32].