title: Adrenal function testing in pediatric cancer survivors.
abstract: BACKGROUND
  Central adrenal insufficiency is observed after cranial radiation therapy for cancer. Screening at risk patients is recommended, but the best screening strategy is unknown.
  
  
  METHODS
  A retrospective review of pediatric cancer survivors who underwent hypothalamic/pituitary/adrenal axis testing was conducted. Data included: cancer diagnosis, radiotherapy dose, other endocrinopathies, and adrenal function testing. Adrenal testing included sequential low-dose corticotropin test (LDCT) and standard-dose corticotropin test (SDCT). 8 a.m. serum cortisol levels were compared to LDCT results. LDCT results were compared by radiotheroapy dose and according to the presence of endocrine comorbidities.
  
  
  RESULTS
  Seventy-eight subjects (56% male, mean age at diagnosis 6.5 years) underwent testing. 67.9% had been treated with radiotherapy to the hypothalamus/pituitary. Mean time to diagnosis of adrenal insufficiency was 6.8 years after cancer diagnosis. Adequate adrenal function was found in 65% of patients by LDCT and 89% by SDCT. Only 21% of patients had basal serum cortisols collected at 8 a.m. Agreement between 8 a.m. baseline cortisol and LDCT was fair. Agreement between random baseline cortisol and LDCT was poor. Prevalence of central adrenal insufficiency diagnosed by LDCT increased with radiotherapy dose (8% for 10-19.9 Gy; 83% for >or=40 Gy) and the number of endocrine comorbidities.
  
  
  CONCLUSIONS
  In pediatric cancer survivors, central adrenal insufficiency was common even in patients receiving <40 Gy to the hypothalamus/pituitary. We recommend use of LDCT, not 8 a.m. serum cortisol to screen patients who received >30 Gy of radiotherapy and those with other central endocrinopathies.
authors.affiliation: Division of Endocrinology, Department of Pediatrics, Emory University, Atlanta, Georgia, USA. bcpatte@emory.edu
authors.forename: Briana C
authors.initials: BC
authors.lastname: Patterson
authors.forename: Lauren
authors.initials: L
authors.lastname: Truxillo
authors.forename: Karen
authors.initials: K
authors.lastname: Wasilewski-Masker
authors.forename: Ann C
authors.initials: AC
authors.lastname: Mertens
authors.forename: Lillian R
authors.initials: LR
authors.lastname: Meacham
mesh_terms: D000293:Adolescent; D000304:Adrenal Cortex Function Tests / Q000706:statistics & numerical data*; D000309:Adrenal Insufficiency / Q000175:diagnosis* / Q000453:epidemiology / Q000209:etiology; D000324:Adrenocorticotropic Hormone / Q000008:administration & dosage; D000328:Adult; D002648:Child; D016371:Cranial Irradiation / Q000009:adverse effects*; D004305:Dose-Response Relationship, Drug; D006801:Humans; D006854:Hydrocortisone / Q000097:blood / Q000378:metabolism; D007027:Hypothalamic Diseases / Q000150:complications; D007030:Hypothalamo-Hypophyseal System / Q000503:physiopathology / Q000528:radiation effects*; D009369:Neoplasms / Q000532:radiotherapy*; D010900:Pituitary Diseases / Q000150:complications; D010912:Pituitary-Adrenal Function Tests / Q000706:statistics & numerical data*; D010913:Pituitary-Adrenal System / Q000503:physiopathology; D011832:Radiation Injuries / Q000150:complications*; D011879:Radiotherapy Dosage; D012189:Retrospective Studies; D012306:Risk; D017741:Survivors / Q000706:statistics & numerical data; D055815:Young Adult
chemical_list: D000324:Adrenocorticotropic Hormone; D006854:Hydrocortisone