title: Validation of nomogram-based prediction of survival probability after salvage re-irradiation of head and neck cancer.
abstract: OBJECTIVE
  Treatment outcomes after salvage re-irradiation in patients with recurrent head and neck cancer vary widely due to heterogeneous patient characteristics, and it is difficult to evaluate optimal re-irradiation schedules. This study aimed to validate a nomogram, originally developed by Tanvetyanon et al., used to predict the survival probability of patients with recurrent head and neck cancer after re-irradiation.
  
  
  METHODS
  Twenty-eight patients with recurrent head and neck cancer who underwent salvage re-irradiation between June 2007 and November 2011 were evaluated. The median total dose used for initial radiotherapy was 60 Gy (range, 22-72). Re-irradiation sites included the nasopharynx or Rouviere's node (n = 14), external ear (n = 4), neck lymph node (n = 3) and other sites (n = 7). Overall survival after re-irradiation was calculated using the Kaplan-Meier method, and the 2-year survival probability was estimated using Tanvetyanon's nomogram.
  
  
  RESULTS
  Twenty-two patients were treated with stereotactic body radiotherapy using a median total dose of 30 Gy (range, 15-40) in 1-7 fractions and six patients were treated with conventional external beam radiotherapy using 45 Gy (range, 23.4-60) in 10-30 fractions. The 2-year overall survival was 21.7% (95% confidence interval: 9.3-41.3), and the 2-year survival probability was 16.8% (95% confidence interval: 9.9-23.6). The 2-year overall survival in 20 patients with unfavorable prognosis (median 2-year survival probability, 5.5%) and in 8 patients with favorable prognosis (median 2-year survival probability, 45%) were 11.0 and 45.7%, respectively (P = 0.05).
  
  
  CONCLUSIONS
  Our findings show that Tanvetyanon's nomogram accurately estimates the survival probability in patients with recurrent head and neck cancer after re-irradiation.
authors.affiliation: Department of Radiology Oncology, Saitama Medical University International Medical Center, 1397-1 Yamane, Hidaka-City, Saitama 350-1298, Japan. nshikama0525@gmail.com
authors.forename: Naoto
authors.initials: N
authors.lastname: Shikama
authors.forename: Yu
authors.initials: Y
authors.lastname: Kumazaki
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Tsukamoto
authors.forename: Takeshi
authors.initials: T
authors.lastname: Ebara
authors.forename: Soichi
authors.initials: S
authors.lastname: Makino
authors.forename: Takanori
authors.initials: T
authors.lastname: Abe
authors.forename: Mitsuhiko
authors.initials: M
authors.lastname: Nakahira
authors.forename: Masashi
authors.initials: M
authors.lastname: Sugasawa
authors.forename: Shingo
authors.initials: S
authors.lastname: Kato
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002294:Carcinoma, Squamous Cell / Q000401:mortality* / Q000532:radiotherapy*; D019583:Dose Fractionation, Radiation; D005260:Female; D006258:Head and Neck Neoplasms / Q000401:mortality* / Q000532:radiotherapy*; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000401:mortality / Q000532:radiotherapy; D049451:Nomograms; D011237:Predictive Value of Tests; D011336:Probability; D016634:Radiosurgery / Q000379:methods*; D015203:Reproducibility of Results; D019233:Retreatment; D018570:Risk Assessment; D012307:Risk Factors; D016879:Salvage Therapy / Q000379:methods*; D016896:Treatment Outcome