title: Hypopituitarism after radiotherapy for extracranial head and neck cancers in pediatric patients.
abstract: OBJECTIVE
  To investigate the incidence of postradiation therapy (postRT) hypopituitarism (hp-pit) in pediatric patients treated for extracranial head and neck tumors.
  
  
  METHODS
  We retrospectively reviewed 30 pediatric patients treated with RT for extracranial head and neck tumors between 1970 and 2000. RT doses to the hypothalamic-pituitary axis were estimated by re-evaluating the treatment plans.
  
  
  RESULTS
  Clinical hp-pit was observed in 16 (53.3%) patients; the median detection latency was 3.3 years and the median dose to the pituitary was 40.7 Gy. Univariate analysis of clinical hp-pit revealed that the total dose to the pituitary was significant (P = 0.034) as was the patient's age at the time of RT (P = 0.018) showing higher susceptibility and more damage in younger patients. Though fractionation (P = 0.018) and adjuvant chemotherapy (P = 0.016) were significant in univariate analysis, the total dose received by patients in these 2 groups was higher than the median dose for all patients. A limited multivariate analysis with 3 variables indicated that the total dose to the pituitary was significant, but chemoradiation and fractionation were not. The 5- and 10-year rates of freedom from clinical hp-pit were 42% and 37%, respectively.
  
  
  CONCLUSIONS
  Clinical manifestations of late radiation toxicity to the hypothalamic-pituitary axis were observed among the pediatric patients with hormone deficiencies. The development of hp-pit depends on the total dose received by the hypothalamic-pituitary axis and the age of the patient. Dependence on chemoradiation and fractionation were inconclusive. Relatively long latency before clinical manifestations indicates that periodic testing after RT in pediatric patients is necessary for early detection and management of hormonal deficiencies.
authors.affiliation: Department of Radiation Oncology, University of Florida College of Medicine, Gainesville, FL, USA.
authors.forename: Niranjan
authors.initials: N
authors.lastname: Bhandare
authors.forename: Laurence
authors.initials: L
authors.lastname: Kennedy
authors.forename: Robert S
authors.initials: RS
authors.lastname: Malyapa
authors.forename: Christopher G
authors.initials: CG
authors.lastname: Morris
authors.forename: William M
authors.initials: WM
authors.lastname: Mendenhall
mesh_terms: D000293:Adolescent; D017024:Chemotherapy, Adjuvant; D002648:Child; D002675:Child, Preschool; D003131:Combined Modality Therapy; D005260:Female; D006258:Head and Neck Neoplasms / Q000532:radiotherapy*; D006801:Humans; D007018:Hypopituitarism / Q000209:etiology*; D007030:Hypothalamo-Hypophyseal System / Q000528:radiation effects*; D008297:Male; D011832:Radiation Injuries / Q000209:etiology*; D011878:Radiotherapy / Q000009:adverse effects; D011879:Radiotherapy Dosage; D012189:Retrospective Studies; D015996:Survival Rate; D013961:Thyroid Gland / Q000528:radiation effects*