SAT-104 Pituitary Hormone Replacement Therapy in the First Year After Diagnosis of Pediatric Craniopharyngioma

Abstract Disclosure: E. Vijay: None. J. Crowley: None. S.E. McCormack: None. Background: Survivors of childhood craniopharyngioma often require long-term pituitary hormone replacement due to injury from the tumor or its treatment. Longitudinal data on typical dosing requirements, along with the association with weight gain, are limited. The objective of this study was to assess levothyroxine, hydrocortisone, desmopressin, and growth hormone (GH) requirements in the first year after diagnosis for those receiving replacement. Methods: This was a retrospective observational study of children diagnosed with craniopharyngioma and receiving care at CHOP between 2008 and 2020. Doses were measured at diagnosis (± 1 month), 3 (± 2), 6 (±2), and 12 (±2) months post-diagnosis. Linear mixed-effects models were used to assess how requirements changed over time and were related to BMI. Results: At craniopharyngioma diagnosis, children (N=57) were 39% (22/57) female, with median age 8.5y (range, 0.4 to 17.9). For those receiving any pituitary hormone replacement, baseline and follow up mean BMI Z-score were 1.33 (SD, 1.48) and 1.59 (1.02), respectively, and baseline and follow up height Z-scores were -0.89 (1.67) and -1.12 (1.49), respectively. At baseline (median, IQR), dose for levothyroxine (50/57) was 52 (44,54) mcg/m2/day, hydrocortisone (49/57), was 9.4 (7.9,10.2) mg/m²/day, and desmopressin (42/57), was 0.3 (0.2,0.4) mg/day. At 12 months, median levothyroxine dose was 56 (47,66) mcg/m2/day, hydrocortisone, 8.0 (7.2, 9.3) mg/m²/day, and desmopressin, 0.3 (0.2,0.4) mg/day. On average, size-normalized levothyroxine and hydrocortisone doses did not change statistically over 12 months, but desmopressin doses (absolute) did increase (p<0.001), driven by the minority with the highest requirements. After accounting for BMI-Z at diagnosis, no hormone replacement dose was associated with BMI-Z at 1 year. Only 4 of 57 started GH within the first 12 months. Conclusion: Size adjusted levothyroxine and hydrocortisone doses remained mostly stable in the year following diagnosis of pediatric craniopharyngioma; a minority of individuals required increases in desmopressin. Natural history information regarding pituitary hormone replacement may inform efforts to counsel childhood craniopharyngioma survivors and families. Presentation: Saturday, July 12, 2025