The prognosis after SCCT is extremely poor.<h4>Case study</h4>We report about SCCT that occurred 45 months after the initial diagnosis of ADC in an East Asian never-smoker woman with advanced-stage <i>EGFR</i> Del-19-mutant lung ADC treated with combined chemoradiotherapy before the era of insurance coverage for EGFR-TKIs in this country and subsequently gefitinib; deletion at codon 746-750 in exon 19 of the <i>EGFR</i> gene was ascertained in the original formalin-fixed paraffin-embedded lung biopsy tissue. Here, EGFR is linked to medical procedure.