title: Prognosis of lung cancer patients with a past history of colorectal cancer.
abstract: OBJECTIVE
  The prognosis in lung cancer patients with a prior history of extrapulmonary cancer is controversial. In the current multicenter joint research in Japan, we focused on the relationship between a history of colorectal cancer and its prognostic impact in patients with subsequent lung cancer.
  
  
  METHODS
  Between 2000 and 2013, we designed a retrospective multicenter study at three institutes in Japan to evaluate the prognostic factors in lung cancer patients with a previous surgery for colorectal cancer.
  
  
  RESULTS
  The cohorts consisted of 123/4431 lung cancer patients with/without a previous history of surgery for colorectal cancer. The median follow-up period was 6.1 years after lung cancer surgery. The 5-year overall survival in lung cancer patients with/without colorectal cancer was not significantly different, regardless of the stage of lung cancer (overall: 71.3 versus 74.7%, P = 0.1426; Stage I lung cancer: 83.3 versus 84.8%, P = 0.3779; Stage II or more lung cancer: 47.7 versus 54.4%, P = 0.1445). Based on multivariate Cox regression analysis in 4554 lung cancer patients, a past history of colorectal cancer was not a significant prognostic factor (P = 0.5335). Among the 123 lung cancer patients with colorectal cancer, age and absence of adjuvant chemotherapy for colorectal cancer were significant prognostic factors based on multivariate analysis (P = 0.0001 and 0.0236). Furthermore, there was no difference in the overall survival of lung cancer patients according to the stage of colorectal cancer (Stage I: 74.7%; Stage II/III: 66.5%, P = 0.7239).
  
  
  CONCLUSIONS
  A history of antecedent colorectal cancer did not contribute to the prognosis in patients with subsequent lung cancers.
authors.affiliation: Department of General Thoracic Surgery, Juntendo University School of Medicine, Tokyo.
authors.forename: Aritoshi
authors.initials: A
authors.lastname: Hattori
authors.affiliation: Department of General Thoracic Surgery, Juntendo University School of Medicine, Tokyo kjsuzuki@juntendo.ac.jp.
authors.forename: Kenji
authors.initials: K
authors.lastname: Suzuki
authors.affiliation: Division of Thoracic Surgery, National Cancer Center Hospital East, Kashiwa, Chiba.
authors.forename: Keiju
authors.initials: K
authors.lastname: Aokage
authors.affiliation: Department of Surgical Oncology, Hiroshima University, Hiroshima, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Mimae
authors.affiliation: Division of Thoracic Surgery, National Cancer Center Hospital East, Kashiwa, Chiba.
authors.forename: Kanji
authors.initials: K
authors.lastname: Nagai
authors.affiliation: Division of Thoracic Surgery, National Cancer Center Hospital East, Kashiwa, Chiba.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Tsuboi
authors.affiliation: Department of Surgical Oncology, Hiroshima University, Hiroshima, Japan.
authors.forename: Morihito
authors.initials: M
authors.lastname: Okada
mesh_terms: D000230:Adenocarcinoma / Q000601:surgery; D000328:Adult; D000368:Aged; D002294:Carcinoma, Squamous Cell / Q000601:surgery; D017024:Chemotherapy, Adjuvant; D015179:Colorectal Neoplasms / Q000601:surgery*; D005260:Female; D006801:Humans; D007564:Japan; D053208:Kaplan-Meier Estimate; D008175:Lung Neoplasms / Q000473:pathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009367:Neoplasm Staging; D011013:Pneumonectomy / Q000379:methods; D011379:Prognosis; D016016:Proportional Hazards Models; D012189:Retrospective Studies
keywords: colorectal cancer; lung cancer; multiple primary cancers; prognosis