title: Analysis of non-genetic risk factors for adverse skin reactions to radiotherapy among 284 breast cancer patients.
abstract: OBJECTIVE
  We analyzed non-genetic risk factors for adverse skin reactions to irradiation at 4 collaborating Japanese institutions, to design future investigation into genetic risk factors for adverse skin reactions to irradiation in a multicenter setting.
  
  
  METHODS
  From April 2001, 284 breast cancer patients, who underwent radiotherapy with breast-conserving surgery, were enrolled from 4 collaborating institutions in Japan. We graded skin reactions according to international scoring systems. Clinical factors were tested against adverse effects.
  
  
  RESULTS
  Grade 1+ skin reactions were observed in 261 (92%) of the patients in less than 3 months, 118 (42%) at 3 months, and 29 (10%) at 6 months in the late phase. Univariate analysis of treatment risk factors (such as the use of a multi-leaf colimeter, wedge-filter, or immobilization device) for skin reactions revealed a significant association (p< 0.0001). After a variable selection procedure with logistic regression, the institution, operative procedure, and magnitude of photon energy remained significantly associated with acute skin reactions. Only the institution was an explanatory variable for skin reactions at 3 and 6 months in the final logistic model.
  
  
  CONCLUSIONS
  After stratification, substantial remaining variations in the occurrence of skin reactions of a given level suggested that individual genetic factors contribute markedly to individual radiosensitivity. Analysis of genetic factors associated with adverse effects would be possible by stratifying patients according to institution. Selection of eligible institutions, where appropriate treatment modalities could be performed, would also be possible when planning such a study.
authors.affiliation: RadGenomics Project, Frontier Research Center, National Institute of Radiological Sciences, Japan. mayumii@nirs.go.jp.
authors.forename: Mayumi
authors.initials: M
authors.lastname: Iwakawa
authors.affiliation: RadGenomics Project, Frontier Research Center, National Institute of Radiological Sciences, Japan.
authors.forename: Shuhei
authors.initials: S
authors.lastname: Noda
authors.affiliation: Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, Japan.
authors.forename: Shigeru
authors.initials: S
authors.lastname: Yamada
authors.affiliation: Chiba Cancer Center, Japan.
authors.forename: Naohito
authors.initials: N
authors.lastname: Yamamoto
authors.affiliation: Chiba University Hospital, Japan.
authors.forename: Yukimasa
authors.initials: Y
authors.lastname: Miyazawa
authors.affiliation: Toyonaka Municipal Hospital, Japan.
authors.forename: Hideya
authors.initials: H
authors.lastname: Yamazaki
authors.affiliation: Kawakami Breast Thyroid Clinic, Japan.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Kawakami
authors.affiliation: RadGenomics Project, Frontier Research Center, National Institute of Radiological Sciences, Japan.|Shimizu Kosei General Hospital, Japan.
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Matsui
authors.affiliation: Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, Japan.
authors.forename: Hirohiko
authors.initials: H
authors.lastname: Tsujii
authors.affiliation: Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, Japan.
authors.forename: Junetsu
authors.initials: J
authors.lastname: Mizoe
authors.affiliation: Foundation of Biomedical Research and Innovation, Japan.|Medical Toukei Corporation, Japan.
authors.forename: Eisei
authors.initials: E
authors.lastname: Oda
authors.affiliation: Foundation of Biomedical Research and Innovation, Japan.|Dainippon Sumitomo Pharma Co., Ltd, Japan.
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Fukunaga
authors.affiliation: RadGenomics Project, Frontier Research Center, National Institute of Radiological Sciences, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Imai
mesh_terms: D000328:Adult; D000368:Aged; D001918:Brachytherapy / Q000009:adverse effects*; D001943:Breast Neoplasms / Q000188:drug therapy / Q000532:radiotherapy* / Q000601:surgery; D003131:Combined Modality Therapy; D005260:Female; D006801:Humans; D008875:Middle Aged; D011855:Radiodermatitis / Q000209:etiology*; D012307:Risk Factors; D012867:Skin / Q000528:radiation effects*