title: Is there a subgroup of long-term evolution among patients with advanced lung cancer?: hints from the analysis of survival curves from cancer registry data.
abstract: BACKGROUND
  Recently, with the access of low toxicity biological and targeted therapies, evidence of the existence of a long-term survival subpopulation of cancer patients is appearing. We have studied an unselected population with advanced lung cancer to look for evidence of multimodality in survival distribution, and estimate the proportion of long-term survivors.
  
  
  METHODS
  We used survival data of 4944 patients with non-small-cell lung cancer (NSCLC) stages IIIb-IV at diagnostic, registered in the National Cancer Registry of Cuba (NCRC) between January 1998 and December 2006. We fitted one-component survival model and two-component mixture models to identify short- and long- term survivors. Bayesian information criterion was used for model selection.
  
  
  RESULTS
  For all of the selected parametric distributions the two components model presented the best fit. The population with short-term survival (almost 4 months median survival) represented 64% of patients. The population of long-term survival included 35% of patients, and showed a median survival around 12 months. None of the patients of short-term survival was still alive at month 24, while 10% of the patients of long-term survival died afterwards.
  
  
  CONCLUSIONS
  There is a subgroup showing long-term evolution among patients with advanced lung cancer. As survival rates continue to improve with the new generation of therapies, prognostic models considering short- and long-term survival subpopulations should be considered in clinical research.
authors.affiliation: Clinical Research Division, Center of Molecular Immunology, Calle 216 esq 15, Atabey, Havana 11600, Cuba. lsanchez@cim.sld.cu.
authors.forename: Lizet
authors.initials: L
authors.lastname: Sanchez
authors.forename: Patricia
authors.initials: P
authors.lastname: Lorenzo-Luaces
authors.forename: Carmen
authors.initials: C
authors.lastname: Viada
authors.forename: Yaima
authors.initials: Y
authors.lastname: Galan
authors.forename: Javier
authors.initials: J
authors.lastname: Ballesteros
authors.forename: Tania
authors.initials: T
authors.lastname: Crombet
authors.forename: Agustin
authors.initials: A
authors.lastname: Lage
mesh_terms: D002289:Carcinoma, Non-Small-Cell Lung / Q000453:epidemiology / Q000401:mortality / Q000473:pathology; D003462:Cuba / Q000453:epidemiology; D006801:Humans; D008175:Lung Neoplasms / Q000453:epidemiology* / Q000401:mortality / Q000473:pathology*; D015233:Models, Statistical; D009367:Neoplasm Staging; D011159:Population Surveillance; D011379:Prognosis; D012042:Registries; D017741:Survivors