title: Epidermal growth factor receptor mutation status in circulating free DNA in serum: from IPASS, a phase III study of gefitinib or carboplatin/paclitaxel in non-small cell lung cancer.
abstract: BACKGROUND
  In IPASS (IRESSA Pan-Asia Study), clinically selected patients with pulmonary adenocarcinoma received first-line gefitinib or carboplatin/paclitaxel. This preplanned, exploratory analysis was conducted to increase understanding of the use of surrogate samples, such as serum, versus tumor biopsy samples for determining EGFR mutation status in the Japanese cohort (n = 233).
  
  
  METHODS
  EGFR mutations were assessed using tumor tissue-derived DNA (n = 91) and circulating free (cf) DNA from pretreatment serum samples (n = 194).
  
  
  RESULTS
  Fewer patients were EGFR mutation positive when assessed using pretreatment cfDNA (23.7%) versus tumor tissue-derived DNA (61.5%). cfDNA results identified no false positives but a high rate of false negatives (56.9%). There was a significant interaction between cfDNA EGFR mutation status and treatment for progression-free survival (PFS) (p = 0.045). PFS was significantly longer and objective response rate (ORR) higher with gefitinib than carboplatin/paclitaxel in the cfDNA EGFR mutation-positive subgroup (PFS: hazard ratio [HR], 0.29; 95% confidence interval [CI], 0.14-0.60; p < 0.001; ORR: odds ratio [OR], 1.71; 95% CI, 0.48-6.09; 75.0% versus 63.6%; p = 0.40). There was a slight numerical advantage in PFS and ORR for gefitinib over carboplatin/paclitaxel in the cfDNA EGFR mutation-negative subgroup, likely due to the high rate of false negatives within this subgroup.
  
  
  CONCLUSIONS
  These results merit further investigation to determine whether alternative sources of tumor DNA, such as cfDNA in serum, could be used for determining EGFR mutation status in future; currently, where a sample is available, analysis of tumor material is recommended.
authors: Division of Thoracic Oncology, National Cancer Center Hospital East, Chiba, Japan. kgoto@east.ncc.go.jp
authors: Koichi
authors: K
authors: Goto
authors: Yukito
authors: Y
authors: Ichinose
authors: Yuichiro
authors: Y
authors: Ohe
authors: Nobuyuki
authors: N
authors: Yamamoto
authors: Shunichi
authors: S
authors: Negoro
authors: Kazuto
authors: K
authors: Nishio
authors: Yohji
authors: Y
authors: Itoh
authors: Haiyi
authors: H
authors: Jiang
authors: Emma
authors: E
authors: Duffield
authors: Rose
authors: R
authors: McCormack
authors: Nagahiro
authors: N
authors: Saijo
authors: Tony
authors: T
authors: Mok
authors: Masahiro
authors: M
authors: Fukuoka
mesh_terms: D000180:Acrylic Resins; D000368:Aged; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D014408:Biomarkers, Tumor / Q000097:blood*; D002289:Carcinoma, Non-Small-Cell Lung / Q000097:blood / Q000188:drug therapy* / Q000235:genetics*; D004252:DNA Mutational Analysis; D018572:Disease-Free Survival; D066246:ErbB Receptors / Q000097:blood / Q000235:genetics*; D005188:False Negative Reactions; D005260:Female; D000077156:Gefitinib; D006801:Humans; D008175:Lung Neoplasms / Q000097:blood / Q000188:drug therapy* / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D009154:Mutation; D017239:Paclitaxel / Q000008:administration & dosage; D011145:Polyvinyls / Q000008:administration & dosage; D047428:Protein Kinase Inhibitors / Q000627:therapeutic use; D011799:Quinazolines / Q000627:therapeutic use; D016896:Treatment Outcome
chemical_list: D000180:Acrylic Resins; D014408:Biomarkers, Tumor; D011145:Polyvinyls; D047428:Protein Kinase Inhibitors; D011799:Quinazolines; C006912:carboxypolymethylene; D066246:ErbB Receptors; D017239:Paclitaxel; D000077156:Gefitinib