title: Outcomes and prognostic factors of post-irradiation and de novo sarcomas of the head and neck: a histologically matched case-control study.
abstract: BACKGROUND
  This study was designed to compare post-irradiation sarcomas (PIS) and de novo sarcomas (DN) of the head and neck in terms of tumor characteristics, prognostic factors, and survival outcomes.
  
  
  METHODS
  All (N=83) head and neck sarcoma patients treated at National Cancer Centre, Singapore (Feb 2002-May 2011) were included: DN (N=60; 72%); PIS (N=23; 28%). Clinicopathologic features and outcomes of all patients and histologically matched pairs were compared. Prognostic factors were identified using univariate and multivariate analyses.
  
  
  RESULTS
  Median age, gender, smoking status, and tumor size were not significantly different. Significant differences were seen in histology (most prevalent: PIS-sarcoma-NOS; DN-angiosarcoma) and tumor subsite (most prevalent: PIS-nasal cavity and sinuses; DN-skin). Median latency of PIS development was 16.7 years. PIS patients had shorter overall survival (OS) and disease-specific survival (DSS) compared with DN patients, most clearly seen on histologically matched pair analysis: 2-year OS (PIS: 54%; DN: 83%; P=0.028). Multivariate analyses showed that age>50 years (hazard ratio (HR)=3.68; P=0.007), ever-smokers (HR=2.79; P=0.017), and larger tumor-size (cm) (HR=1.12; P=0.045) were associated with worse OS, and age at >50 years (HR=2.77; P=0.04) and ever-smokers (HR=2.94; P=0.021) were associated with worse DSS. When treated with curative intent, no significant survival difference was noted between DN and PIS patients.
  
  
  CONCLUSIONS
  In our cohort, PIS constituted 28% of head and neck sarcomas. Poorer prognosis traditionally associated with PIS compared with DN was not seen amongst patients treated with curative intent.
authors.affiliation: Department of Surgical Oncology, National Cancer Centre Singapore, 11 Hospital Drive, Singapore, 169610, Singapore.
authors.forename: Ming Sheng
authors.initials: MS
authors.lastname: Yeang
authors.forename: Kaijun
authors.initials: K
authors.lastname: Tay
authors.forename: Whee Sze
authors.initials: WS
authors.lastname: Ong
authors.forename: Anuradha
authors.initials: A
authors.lastname: Thiagarajan
authors.forename: Daniel Shao-Weng
authors.initials: DS
authors.lastname: Tan
authors.forename: Tam Cam
authors.initials: TC
authors.lastname: Ha
authors.forename: Patrick Tze-Hern
authors.initials: PT
authors.lastname: Teo
authors.forename: Khee-Chee
authors.initials: KC
authors.lastname: Soo
authors.forename: Hiang Khoon
authors.initials: HK
authors.lastname: Tan
authors.forename: N Gopalakrishna
authors.initials: NG
authors.lastname: Iyer
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006258:Head and Neck Neoplasms / Q000150:complications / Q000401:mortality / Q000532:radiotherapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D009364:Neoplasm Recurrence, Local / Q000175:diagnosis / Q000209:etiology / Q000401:mortality*; D009381:Neoplasms, Radiation-Induced / Q000175:diagnosis / Q000209:etiology / Q000401:mortality*; D011379:Prognosis; D011878:Radiotherapy / Q000009:adverse effects*; D012307:Risk Factors; D012509:Sarcoma / Q000175:diagnosis / Q000209:etiology / Q000401:mortality*; D015996:Survival Rate; D055815:Young Adult