title: The impact of comorbidity on outcome in 12 623 Danish head and neck cancer patients: a population based study from the DAHANCA database.
abstract: BACKGROUND
  Head and neck squamous cell carcinoma (HNSCC) is primarily caused by smoking and alcohol. Besides having a carcinogenic effect, smoking also leads to other diseases and thus contributes to a high prevalence of comorbidities among HNSCC patients. Furthermore, the world population is becoming older resulting in more elderly patients with HNSCC. The aim of this study was to investigate the prevalence and impact of comorbidity in a retrospective nationwide population-based study of all Danish HNSCC patients diagnosed from 1992 to 2008.
  
  
  METHODS
  A total of 12 623 patients diagnosed with HNSCC in the period from 1992 to 2008 were identified through the Danish Head and Neck Cancer group (DAHANCA) database. By linking to the Danish registers, information on somatic comorbidity present prior to the HNSCC diagnosis was obtained and adapted to the Charlson Comorbidity Index (CCI). The influence of comorbidity on overall survival and cancer specific death was evaluated and the type and prevalence of comorbidity described.
  
  
  RESULTS
  In total, 36% of patients had comorbidity according to CCI. Increasing age was significantly associated with increasing CCI. In multivariate analyses, the CCI score remained a strong independent prognostic factor for overall survival, the HR being 1.16 (95% CI 1.08; 1.25), 1.34 (1.22; 1.46), 1.63 (1.51; 1.80) for patients with CCI score 1, 2, and 3+, respectively. The CCI score did not influence cancer specific death.
  
  
  CONCLUSIONS
  Comorbidity is common among HNSCC patients and has a negative prognostic impact on overall survival. Cancer specific death was not affected by comorbidity suggesting that patients die from their comorbidities rather than their cancer. In the future, more elderly patients with comorbidity will require treatment which will demand a change in the healthcare system with a multidisciplinary approach required in order to take care of both their cancer and their comorbidities.
authors: Department of Experimental Clinical Oncology, Aarhus University Hospital, Denmark. charlotte@oncology.dk
authors: Charlotte Rotbøl
authors: CR
authors: Bøje
authors: Susanne O
authors: SO
authors: Dalton
authors: Therese K
authors: TK
authors: Grønborg
authors: Hanne
authors: H
authors: Primdahl
authors: Claus A
authors: CA
authors: Kristensen
authors: Elo
authors: E
authors: Andersen
authors: Jørgen
authors: J
authors: Johansen
authors: Lisbeth J
authors: LJ
authors: Andersen
authors: Jens
authors: J
authors: Overgaard
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002294:Carcinoma, Squamous Cell / Q000175:diagnosis* / Q000453:epidemiology* / Q000401:mortality; D015897:Comorbidity; D016208:Databases, Factual / Q000706:statistics & numerical data; D003718:Denmark / Q000453:epidemiology; D005260:Female; D006258:Head and Neck Neoplasms / Q000175:diagnosis* / Q000453:epidemiology* / Q000401:mortality; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012042:Registries; D000077195:Squamous Cell Carcinoma of Head and Neck; D016019:Survival Analysis