title: Indications of external beam radiation therapy in non-anaplastic thyroid cancer and impact of innovative radiation techniques.
abstract: BACKGROUND
  The mainstay of treatment for differentiated thyroid carcinomas is surgery. There is hardly any room for radiation therapy in differentiated thyroid carcinomas. We aimed to update recommendations for RT in the context of histological variants, increased use of radioiodine and new irradiations techniques.
  
  
  METHODS
  A search of the French and English literature was performed using thyroid carcinoma, radiation therapy, surgery, variants and radioiodine.
  
  
  RESULTS
  Papillary, follicular, Hürthle and medullary carcinomas represent about 80%, 11%, 3% and 4% of all thyroid carcinomas, respectively. Ten-year survival rates for patients with papillary, follicular and Hürthle cell carcinomas are 93%, 85%, and 76%, respectively. The occurrence of criteria such as older age (45 or 60 years-old), massive primary disease, extensive extracapsular spread and macroscopic iodine-negative components inconsistently indicate external beam irradiation (EBRT). The impact of EBRT on poorer-prognosis histological variants is an emerging issue. Noteworthy, the incidence of laryngeal and wound healing complications has been an important limitation to EBRT. However, intensity modulated radiation therapy (IMRT) offers clear dosimetric advantages on tumor coverage and organ sparing such as the larynx, thus reducing late toxicities to less than 5%. Iodine contrast agents should be avoided during 4-6 weeks before radioiodine. PET CT is increasingly used in iodine-negative tumors.
  
  
  CONCLUSIONS
  There are elective indications for EBRT and IMRT has the potential to improve local control.
authors.affiliation: Department of Radiation Oncology, Jean Minjoz University Teaching Hospital, Boulevard Flemming, Besançon, F-25000, France.
authors.forename: X S
authors.initials: XS
authors.lastname: Sun
authors.forename: S R
authors.initials: SR
authors.lastname: Sun
authors.forename: N
authors.initials: N
authors.lastname: Guevara
authors.forename: P Y
authors.initials: PY
authors.lastname: Marcy
authors.forename: I
authors.initials: I
authors.lastname: Peyrottes
authors.forename: S
authors.initials: S
authors.lastname: Lassalle
authors.forename: A
authors.initials: A
authors.lastname: Lacout
authors.forename: J L
authors.initials: JL
authors.lastname: Sadoul
authors.forename: J
authors.initials: J
authors.lastname: Santini
authors.forename: D
authors.initials: D
authors.lastname: Benisvy
authors.forename: A
authors.initials: A
authors.lastname: Lepinoy
authors.forename: J
authors.initials: J
authors.lastname: Thariat
mesh_terms: D000328:Adult; D000465:Algorithms; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes; D008297:Male; D008875:Middle Aged; D011878:Radiotherapy / Q000706:statistics & numerical data*; D035703:Therapies, Investigational / Q000379:methods / Q000706:statistics & numerical data*; D013964:Thyroid Neoplasms / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D013965:Thyroidectomy
chemical_list: D007457:Iodine Radioisotopes