title: Volumetric Tumor Response and Progression in EGFR-mutant NSCLC Patients Treated with Erlotinib or Gefitinib.
abstract: OBJECTIVE
  The aims of this study were to investigate the association between 8-week tumor volume decrease and survival in an independent cohort of epidermal growth factor receptor (EGFR)-mutant advanced non-small cell lung cancer (NSCLC) patients treated with first-line erlotinib or gefitinib, and to assess the rate of their volumetric tumor growth after the volume nadir.
  
  
  METHODS
  In patients with advanced NSCLC harboring sensitizing EGFR mutations treated with first-line erlotinib or gefitinib, computed tomography (CT) tumor volumes of dominant lung lesions were analyzed for (1) the association with survival, and (2) the volumetric tumor growth rate after the volume nadir.
  
  
  RESULTS
  In 44 patients with the 8-week follow-up CT, the 8-week tumor volume decrease (%) was significantly associated with longer overall survival when fitted as a continuous variable in a Cox model (P = 0.01). The growth rate of the logarithm of tumor volume (logeV), obtained using a linear mixed-effects model adjusting for time since baseline, was 0.096/month (SE: 0.013/month; 95% confidence interval [CI]: 0.071-0.12/month), which was similar to the rate of 0.12/month (SE: 0.015/month; 95%CI: 0.090-0.15/month) observed in the previous report.
  
  
  CONCLUSIONS
  The 8-week tumor volume decrease was validated as a marker for longer survival in the independent cohort of EGFR-mutant NSCLC patients treated with first-line erlotinib or gefitinib. The volumetric tumor growth rate after the nadir in this cohort was similar to that of the previous cohort, indicating the reproducibility of the observation among different patient cohorts.
authors.affiliation: Department of Radiology, Brigham and Women's Hospital and Dana-Farber Cancer Institute, Harvard Medical School, 450 Brookline Ave., Boston, MA 02215. Electronic address: Mizuki_Nishino@DFCI.HARVARD.EDU.
authors.forename: Mizuki
authors.initials: M
authors.lastname: Nishino
authors.affiliation: Department of Biostatistics and Computational Biology, Dana-Farber Cancer Institute, Boston, Massachusetts.
authors.forename: Suzanne E
authors.initials: SE
authors.lastname: Dahlberg
authors.affiliation: Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts.
authors.forename: Linnea E
authors.initials: LE
authors.lastname: Fulton
authors.affiliation: Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts.
authors.forename: Subba R
authors.initials: SR
authors.lastname: Digumarthy
authors.affiliation: Department of Radiology, Brigham and Women's Hospital and Dana-Farber Cancer Institute, Harvard Medical School, 450 Brookline Ave., Boston, MA 02215.
authors.forename: Hiroto
authors.initials: H
authors.lastname: Hatabu
authors.affiliation: Department of Medical Oncology and Department of Medicine, Brigham and Women's Hospital and Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts.
authors.forename: Bruce E
authors.initials: BE
authors.lastname: Johnson
authors.affiliation: Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts.
authors.forename: Lecia V
authors.initials: LV
authors.lastname: Sequist
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D002289:Carcinoma, Non-Small-Cell Lung / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000473:pathology; D015331:Cohort Studies; D018450:Disease Progression; D066246:ErbB Receptors / Q000037:antagonists & inhibitors / Q000235:genetics*; D000069347:Erlotinib Hydrochloride / Q000627:therapeutic use*; D005260:Female; D005500:Follow-Up Studies; D000077156:Gefitinib; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009154:Mutation / Q000235:genetics*; D047428:Protein Kinase Inhibitors / Q000627:therapeutic use; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors; D011799:Quinazolines / Q000627:therapeutic use*; D012074:Remission Induction; D012189:Retrospective Studies; D015996:Survival Rate; D014057:Tomography, X-Ray Computed / Q000379:methods; D047368:Tumor Burden / Q000187:drug effects; D055815:Young Adult
chemical_list: D000970:Antineoplastic Agents; D047428:Protein Kinase Inhibitors; D011799:Quinazolines; D000069347:Erlotinib Hydrochloride; D066246:ErbB Receptors; D011505:Protein-Tyrosine Kinases; D000077156:Gefitinib
keywords: EGFR mutations; Lung cancer; non-small cell; tumor volume; tyrosine kinase inhibitors