title: Subcutaneous fibrosis after whole neck irradiation.
abstract: OBJECTIVE
  To identify the risk factors for moderate to severe subcutaneous fibrosis after whole neck irradiation.
  
  
  METHODS
  We analyzed 233 cases of patients who had undergone whole neck irradiation with 4-MV X-ray or 8-10-MeV electrons, or both, and had been followed with regard to their skin condition for at least 1 year. The prescribed dose to the whole neck ranged from 19.2 to 72.4 Gy (median 50). The skin-absorbed dose was specified as that at a depth of 4.1 mm (d4.1-mm(depth)), and a biologically equivalent dose (BED) of d4.1-mm(depth) was also estimated (BED(1.8) 4.1-mm(depth)).
  
  
  RESULTS
  Univariate analysis revealed that previous neck dissection, concurrent chemotherapy, corticosteroid administration as a part of chemotherapy, fractionation, and BED(1.8) 4.1-mm(depth) were significant prognostic variables. Multivariate analysis showed that BED(1.8) 4.1-mm(depth) and previous neck dissection were the only prognostic variables for moderate to severe subcutaneous fibrosis.
  
  
  CONCLUSIONS
  A high dose to a 4.1-mm depth of the skin and a history of neck dissection were identified as the predominant risk factors for moderate to severe subcutaneous fibrosis after whole neck irradiation. A subcutaneous dose should be considered in radiotherapy treatment planning involving the whole neck, especially in cases in which patients have undergone previous neck dissection.
authors.affiliation: Department of Radiology, Hyogo Medical Center for Adults, Akashi, Japan. ka3s-hrt@asahi-net.or.jp
authors.forename: Saeko
authors.initials: S
authors.lastname: Hirota
authors.forename: Kayoko
authors.initials: K
authors.lastname: Tsujino
authors.forename: Takashi
authors.initials: T
authors.lastname: Oshitani
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Hishikawa
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Takada
authors.forename: Michio
authors.initials: M
authors.lastname: Kono
authors.forename: Mitsuyuki
authors.initials: M
authors.lastname: Abe
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D005355:Fibrosis; D006258:Head and Neck Neoplasms / Q000532:radiotherapy*; D006801:Humans; D008197:Lymph Node Excision; D008875:Middle Aged; D009333:Neck; D011832:Radiation Injuries / Q000473:pathology*; D012189:Retrospective Studies; D012867:Skin / Q000473:pathology* / Q000528:radiation effects