Fig. 4

Tumor necrosis indicates early good response in non-small cell lung cancer (NSCLC) receiving targeted therapy. A 53-year-old man diagnosed with NSCLC (positive EGFR exon 20 insertion mutations) and received afatinib therapy. A Pretreatment contrast-enhanced (CE) axial CT scan shows an enhancing tumor (arrow), with diameter of 64 mm. B, C Pseudo-progression with increased tumor size (arrow) was observed in 3 months (B) (67 mm in tumor diameter) and 8 months (C) (74 mm in tumor diameter) after targeted therapy. Simultaneously, the progression of focal tumor necrosis (arrowheads in figure B) to diffuse tumor necrosis (C) was also observed. D Shrinkage of tumor mass (50 mm in diameter) was observed 15 months after therapy