title: Radiation-induced squamous cell carcinoma of the nasopharynx after radiotherapy for nasopharyngeal carcinoma.
abstract: BACKGROUND
  The purpose of this study was to investigate the treatment outcome of radiation-induced squamous cell carcinoma (SCC) of the nasopharynx after radiotherapy (RT) for nasopharyngeal carcinoma (NPC).
  
  
  METHODS
  We conducted a retrospective review of patients who underwent radiation therapy for NPC, which resulted in radiation-induced SCC of the nasopharynx.
  
  
  RESULTS
  Between 1998 and 2011, 24 patients had radiation-induced SCC of the nasopharynx. The median age of diagnosis was 68.2 years. The majority of patients (66.7%) presented with early-stage NPC initially, and they were treated with RT alone (n = 18) or concurrent chemoradiation (n = 6). The mean latency period for the second malignancy was 10.5 years. All the patients were treated with maxillary-swing nasopharyngectomy. Clear resection margin was achieved in 66.7%, and 75% of those with involved margin received adjuvant RT. The mean follow-up duration was 48.2 months. The overall 5-year actuarial local tumor control was 56% and the overall 5-year disease-free survival was 38%.
  
  
  CONCLUSIONS
  Radiation-induced SCC of the nasopharynx is rare after RT for NPC. The prognosis remained poor despite aggressive surgery and adjuvant RT.
authors.affiliation: Diion of Head and Neck Surgery, Department of Surgery, University of Hong Kong Li Ka Shing Faculty of Medicine, Queen Mary Hospital, Hong Kong Special Administrative Region, China.
authors.forename: Jimmy Yu Wai
authors.initials: JY
authors.lastname: Chan
authors.forename: Victor Shing Howe
authors.initials: VS
authors.lastname: To
authors.forename: Stanley Thian Sze
authors.initials: ST
authors.lastname: Wong
authors.forename: William Ignace
authors.initials: WI
authors.lastname: Wei
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002277:Carcinoma; D002294:Carcinoma, Squamous Cell / Q000175:diagnosis / Q000209:etiology* / Q000401:mortality / Q000628:therapy; D005260:Female; D005500:Follow-Up Studies; D006723:Hong Kong; D006801:Humans; D008297:Male; D008875:Middle Aged; D000077274:Nasopharyngeal Carcinoma; D009303:Nasopharyngeal Neoplasms / Q000175:diagnosis / Q000209:etiology* / Q000401:mortality / Q000532:radiotherapy / Q000628:therapy; D010611:Pharyngectomy / Q000379:methods; D011379:Prognosis; D018714:Radiotherapy, Adjuvant / Q000009:adverse effects*; D012189:Retrospective Studies; D012307:Risk Factors; D016019:Survival Analysis; D013997:Time Factors; D016896:Treatment Outcome
keywords: nasopharyngeal carcinoma; nasopharynx; radiation-induced malignancy; radiotherapy; squamous cell carcinoma