OBJECTIVES: To investigate the relationship of dual-phase dual-energy CT (DE-CT) and tumour size in the evaluation of the response to anti-EGFR therapy in patients with advanced non-small cell lung cancer (NSCLC). METHODS: Dual-phase DE-CT was performed in 31 patients with NSCLC before the onset of anti-EGFR (erlotinib) therapy and as follow-up (mean 8 weeks). Iodine uptake (IU; mg/mL) was quantified using prototype software in arterial and venous phases; arterial enhancement fraction (AEF) was calculated. The change of IU before and after therapy onset was compared with anatomical evaluation in maximal transverse diameter and volume (responders vs. non-responders). RESULTS: A significant decrease of IU in venous phase was proved in responders according to all anatomical parameters (p=0.002-0.016). In groups of non-responders, a significant change of IU was not proved with variable trends of development. The most significant change was observed using the anatomical parameter of volume (cut-off 73 %). A significant difference of percentage change in AEF was proved between responding and non-responders (p=0.019-0.043). CONCLUSION: Dual-phase DE-CT with iodine uptake quantification is a feasible method with potential benefit in advanced assessment of anti-EGFR therapy response. We demonstrated a decrease in vascularization in the responding primary tumours and non-significant variable development of vascularization in non-responding tumours. KEY POINTS: • Dual-phase DE-CT is feasible for vascularization assessment of NSCLC with anti-EGFR therapy. • There was a significant decrease of iodine uptake in responding tumours. • There was a non-significant and variable development in non-responding tumours. • There was significant difference of AEF percentage change between responders and non-responders.

• Keywords
• Dual-energy CT, Iodine contrast medium, Lung cancer, Targeted molecular therapy, Therapy response,
• MeSH
• Erlotinib Hydrochloride therapeutic use   MeSH
• Iodine MeSH
• Middle Aged MeSH
• Humans MeSH
• Lymphatic Metastasis MeSH
• Lymph Nodes diagnostic imaging   MeSH
• Lung Neoplasms drug therapy   pathology   MeSH
• Carcinoma, Non-Small-Cell Lung diagnosis   drug therapy   secondary   MeSH
• Tomography, X-Ray Computed methods   MeSH
• Positron-Emission Tomography methods   MeSH
• Antineoplastic Agents therapeutic use   MeSH
• Reproducibility of Results MeSH
• Aged MeSH
• Neoplasm Staging * MeSH
• Check Tag
• Middle Aged MeSH
• Humans MeSH
• Male MeSH
• Aged MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Erlotinib Hydrochloride MeSH
• Iodine MeSH
• Antineoplastic Agents MeSH