title: Socioeconomic status, human papillomavirus, and overall survival in head and neck squamous cell carcinomas in Toronto, Canada.
abstract: BACKGROUND
  Despite universal healthcare in some countries, lower socioeconomic status (SES) has been associated with worse cancer survival. The influence of SES on head and neck cancer (HNC) survival is of immense interest, since SES is associated with the risk and prognostic factors associated with this disease.
  
  
  METHODS
  Newly diagnosed HNC patients from 2003 to 2010 (n=2124) were identified at Toronto's Princess Margaret Cancer Centre. Principal component analysis was used to calculate a composite score using neighbourhood-level SES variables obtained from the 2006 Canada Census. Associations of SES with overall survival were evaluated in HNC subsets and by p16 status (surrogate for human papillomavirus).
  
  
  RESULTS
  SES score was higher for oral cavity (n=423) and p16-positive oropharyngeal cancer (OPC, n=404) patients compared with other disease sites. Lower SES was associated with worse survival [HR 1.14 (1.06-1.22), p=0.0002], larger tumor staging (p<0.001), current smoking (p<0.0001), heavier alcohol consumption (p<0.0001), and greater comorbidity (p<0.0002), but not with treatment regimen (p>0.20). After adjusting for age, sex, and stage, the lowest SES quintile was associated with the worst survival only for OPC patients [HR 1.66 (1.09-2.53), n=832], primarily in the p16-negative subset [HR 1.63 (0.96-2.79)]. The predictive ability of the prognostic models improved when smoking/alcohol was added to the model (c-index 0.71 vs. 0.69), but addition of SES did not (c-index 0.69).
  
  
  CONCLUSIONS
  SES was associated with survival, but this effect was lost after accounting for other factors (age, sex, TNM stage, smoking/alcohol). Lower SES was associated with greater smoking, alcohol consumption, comorbidity, and stage.
authors.affiliation: Ontario Cancer Institute, Princess Margaret Hospital, Toronto, Canada.
authors.forename: K P
authors.initials: KP
authors.lastname: Chu
authors.affiliation: Ontario Cancer Institute, Princess Margaret Hospital, Toronto, Canada.
authors.forename: S
authors.initials: S
authors.lastname: Habbous
authors.affiliation: Ontario Cancer Institute, Princess Margaret Hospital, Toronto, Canada.
authors.forename: Q
authors.initials: Q
authors.lastname: Kuang
authors.affiliation: Ontario Cancer Institute, Princess Margaret Hospital, Toronto, Canada.
authors.forename: K
authors.initials: K
authors.lastname: Boyd
authors.affiliation: Ontario Cancer Institute, Princess Margaret Hospital, Toronto, Canada.
authors.forename: M
authors.initials: M
authors.lastname: Mirshams
authors.affiliation: Department of Radiation Oncology, University of Toronto, Ontario, Canada.
authors.forename: F-F
authors.initials: FF
authors.lastname: Liu
authors.affiliation: Department of Biostatistics, Princess Margaret Hospital, Toronto, Canada.
authors.forename: O
authors.initials: O
authors.lastname: Espin-Garcia
authors.affiliation: Department of Biostatistics, Princess Margaret Hospital, Toronto, Canada.
authors.forename: W
authors.initials: W
authors.lastname: Xu
authors.affiliation: Otolaryngology-Head and Neck Surgery, University of Toronto, Canada.
authors.forename: D
authors.initials: D
authors.lastname: Goldstein
authors.affiliation: Department of Radiation Oncology, University of Toronto, Ontario, Canada.
authors.forename: J
authors.initials: J
authors.lastname: Waldron
authors.affiliation: Department of Radiation Oncology, University of Toronto, Ontario, Canada.
authors.forename: B
authors.initials: B
authors.lastname: O'Sullivan
authors.affiliation: Department of Radiation Oncology, University of Toronto, Ontario, Canada.
authors.forename: S H
authors.initials: SH
authors.lastname: Huang
authors.affiliation: Medicine and Epidemiology, Dalla Lana School of Public Health, University of Toronto, Canada. Electronic address: Geoffrey.liu@uhn.ca.
authors.forename: G
authors.initials: G
authors.lastname: Liu
mesh_terms: D000368:Aged; D000428:Alcohol Drinking; D002170:Canada; D002294:Carcinoma, Squamous Cell / Q000401:mortality* / Q000473:pathology / Q000821:virology; D015897:Comorbidity; D005260:Female; D006258:Head and Neck Neoplasms / Q000401:mortality* / Q000473:pathology / Q000821:virology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D027383:Papillomaviridae / Q000472:pathogenicity*; D030361:Papillomavirus Infections / Q000401:mortality* / Q000473:pathology; D011379:Prognosis; D012307:Risk Factors; D012907:Smoking; D012923:Social Class; D015996:Survival Rate
keywords: Head and neck neoplasms; Human papillomavirus; Principal component analysis; Socioeconomic status; Survival