title: Clinicopathological features and EGFR gene mutation status in elderly patients with resected non-small-cell lung cancer.
abstract: BACKGROUND
  The rapid aging of the population in Japan has been accompanied by an increased rate of surgery for lung cancer among elderly patients. It is thus an urgent priority to map out a treatment strategy for elderly patients with primary lung cancer. Although surgical resection remains standard treatment for early stage non-small-cell lung cancer (NSCLC), it is now essential to confirm the status of epidermal growth factor receptor (EGFR) gene mutations when planning treatment strategies. Furthermore, several studies have reported that EGFR mutations are an independent prognostic marker in NSCLC. However, the relations between age group and the molecular and pathological characteristics of NSCLC remain unclear. We studied the status of EGFR mutations in elderly patients with NSCLC and examined the relations of EGFR mutations to clinicopathological factors and outcomes according to age group.
  
  
  METHODS
  A total of 388 consecutive patients with NSCLC who underwent complete tumor resection in our hospital from 2006 through 2008 were studied retrospectively. Formalin-fixed, paraffin-embedded tissue sections were used to isolate DNA from carcinoma lesions. Mutational analyses of EGFR gene exons 19, 20, and 21 and KRAS gene exons 12 and 13 were performed by loop-hybrid mobility shift assay, a highly sensitive polymerase chain reaction-based method.
  
  
  RESULTS
  EGFR mutations were detected in 185 (47.7%) and KRAS mutations were detected in 33 (8.5%) of the 388 patients. EGFR mutations were found in a significantly higher proportion of patients younger than 80 years (younger group; 178/359, 49.6%) than in patients 80 years or older (older group; 7/29, 24.1%) (P = 0.008). In contrast, KRAS mutations were more common in the older group (6/29, 20.7%) than in the younger group (27/359, 7.5%) (P = 0.014). The older group showed a trend toward a higher rate of 5-year overall survival among elderly patients with EGFR mutations (100%) than among those with wild-type EGFR (66.2%), but the difference was not significant.
  
  
  CONCLUSIONS
  Our results suggest that the EGFR status of patients with NSCLC differs between patients 80 years or older and those younger than 80 years. EGFR mutation status might be a prognostic marker in elderly patients with completely resected NSCLC.
authors.affiliation: Department of Thoracic Oncology, Kanagawa Cancer Center Hospital, 2-3-2 Nakao, Asahi-ku, Yokohama 2418515, Japan. t-nishii@kcch.jp.
authors.forename: Teppei
authors.initials: T
authors.lastname: Nishii
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Yokose
authors.forename: Yohei
authors.initials: Y
authors.lastname: Miyagi
authors.forename: Yataro
authors.initials: Y
authors.lastname: Daigo
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Ito
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Isaka
authors.forename: Kentaro
authors.initials: K
authors.lastname: Imai
authors.forename: Shuji
authors.initials: S
authors.lastname: Murakami
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Kondo
authors.forename: Haruhiro
authors.initials: H
authors.lastname: Saito
authors.forename: Fumihiro
authors.initials: F
authors.lastname: Oshita
authors.forename: Kouzo
authors.initials: K
authors.lastname: Yamada
authors.forename: Shoichi
authors.initials: S
authors.lastname: Matsukuma
authors.forename: Masahiro
authors.initials: M
authors.lastname: Tsuboi
authors.forename: Haruhiko
authors.initials: H
authors.lastname: Nakayama
authors.forename: Munetaka
authors.initials: M
authors.lastname: Masuda
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002289:Carcinoma, Non-Small-Cell Lung / Q000235:genetics* / Q000473:pathology* / Q000601:surgery; D066246:ErbB Receptors / Q000235:genetics*; D005091:Exons; D006801:Humans; D008175:Lung Neoplasms / Q000235:genetics* / Q000473:pathology* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D009154:Mutation; D011379:Prognosis; D011518:Proto-Oncogene Proteins / Q000235:genetics; D016283:Proto-Oncogene Proteins p21(ras); D016019:Survival Analysis; D018631:ras Proteins / Q000235:genetics
chemical_list: C117307:KRAS protein, human; D011518:Proto-Oncogene Proteins; C512478:EGFR protein, human; D066246:ErbB Receptors; D016283:Proto-Oncogene Proteins p21(ras); D018631:ras Proteins