title: The TNM 8 M1b and M1c classification for non-small cell lung cancer in a cohort of patients with brain metastases.
abstract: OBJECTIVE
  According to the recent TNM 8 classification, patients with metastatic non-small cell lung cancer (NSCLC) and single extrathoracic metastasis should be classified as stage M1b, while those with 2 or more metastases comprise stage M1c. The purpose of this study was to analyze the impact of this classification in patients with brain metastases.
  
  
  METHODS
  This retrospective study included 172 patients treated with individualized approaches. Actuarial survival was calculated. Uni- and multivariate analyses were performed.
  
  
  RESULTS
  Thirty patients (17%) were staged as M1b. Those with squamous cell cancer were more likely to harbor M1b disease (29%, adenocarcinoma 14%, other histology 17%, p = 0.16). Median survival was 5.4 months (8.0 months in case of M1b disease and 4.5 months in case of M1c disease, p = 0.001). Multivariate analysis confirmed the role of M1b stage. M1b patients managed with upfront surgery or radiosurgery had significantly longer median survival than those who received whole-brain irradiation (21.0 vs. 3.5 months, p = 0.0001) and the potential to survive beyond 5 years.
  
  
  CONCLUSIONS
  We found the M1b classification to provide clinically relevant information. The multivariate analysis suggested that patients with M1b disease, better performance status and younger age have better survival.
authors.affiliation: Department of Oncology and Palliative Medicine, Nordland Hospital, 8092, Bodø, Norway. carsten.nieder@nlsh.no.|Department of Clinical Medicine, Faculty of Health Sciences, University of Tromsø, 9037, Tromsø, Norway. carsten.nieder@nlsh.no.
authors.forename: C
authors.initials: C
authors.lastname: Nieder
authors.affiliation: Department of Radiation Oncology, University Hospital Freiburg, 79106, Freiburg, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Hintz
authors.affiliation: Department of Radiation Oncology, University Hospital Freiburg, 79106, Freiburg, Germany.|German Cancer Consortium (DKTK), Partner Site Freiburg, Freiburg, Germany.
authors.forename: O
authors.initials: O
authors.lastname: Oehlke
authors.affiliation: Department of Radiation Oncology, University Hospital Freiburg, 79106, Freiburg, Germany.|German Cancer Consortium (DKTK), Partner Site Freiburg, Freiburg, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Bilger
authors.affiliation: Department of Radiation Oncology, University Hospital Freiburg, 79106, Freiburg, Germany.|German Cancer Consortium (DKTK), Partner Site Freiburg, Freiburg, Germany.
authors.forename: A L
authors.initials: AL
authors.lastname: Grosu
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001932:Brain Neoplasms / Q000401:mortality / Q000556:secondary*; D002289:Carcinoma, Non-Small-Cell Lung / Q000145:classification* / Q000401:mortality / Q000556:secondary*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008175:Lung Neoplasms / Q000145:classification* / Q000401:mortality / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging / Q000379:methods*; D011379:Prognosis; D016016:Proportional Hazards Models; D012189:Retrospective Studies
keywords: Brain metastases; Lung cancer; Prognostic factors; Radiotherapy