Postoperative adjuvant chemotherapy with tegafur-uracil has become the standard 
of care for patients with completely resected stage I adenocarcinoma according 
to the positive result from phase III trial conducted in Japan. The 
effectiveness of tegafur-gimeracil-oteracil potassium in advanced non-small cell 
lung cancer (NSCLC) is now under investigation in a phase III trial in the 
first-line treatment in combination with platinum agent as well as in 
second-line treatment as monotherapy. The evidence of epidermal growth factor 
receptor (EGFR)-tyrosine kinase inhibitor (TKI) such as gefitinib and erlotinib 
was first confirmed as the second-line treatment for non-selective patients with 
advanced NSCLC. However, now it is essential to examine some active EGFR gene 
mutations such as exon 19 deletion or L858R in exon 21, the novel predictive 
factor for high efficacy of EGFR-TKI, in terms of the risk-benefit balance. For 
patients with EGFR-mutated advanced NSCLC, the first-line treatment with 
gefitinib had achieved a significant prolongation of progression-free survival 
compared with standard platinum doublet chemotherapy in a few phase III trials, 
and became a new standard of care. Gefitinib is highly effective for patients 
with advanced NSCLC with EGFR mutation even if their performance status is poor, 
although one should always pay careful attention to fatal interstitial lung 
disease.