Growth Outcomes and Relapse Risk in Pediatric Medulloblastoma Survivors with and Without Growth Hormone Therapy: A 23-Year Single-Center Cohort Study

Background: Growth hormone deficiency (GHD) is one of the most common endocrine sequelae in survivors of pediatric medulloblastoma, largely resulting from hypothalamic–pituitary irradiation. Concerns regarding the oncologic safety of growth hormone (GH) replacement have historically limited its use. This study aimed to evaluate growth response to GH therapy and its potential association with tumor relapse in medulloblastoma survivors treated between 2000 and 2023. Methods: We conducted a retrospective single-center cohort study including 74 patients diagnosed with medulloblastoma before 18 years of age. GHD was confirmed by stimulation testing according to standard criteria. Auxological, endocrine, and oncologic data were collected longitudinally. Growth outcomes were compared among patients without GHD (n = 38), patients with untreated GHD (n = 13), and patients with GHD receiving GH treatment (n = 23). Relapse rates were assessed following GH initiation and compared with those of untreated patients. Results: GHD was diagnosed in 48.7% of patients. Baseline height SDS did not differ among groups. Patients with untreated GHD experienced a significant decline in height SDS (−1.93 ± 0.78), whereas GH-treated patients showed a significant increase (+0.39 ± 0.06; p < 0.0001). Final height SDS was significantly lower in untreated GHD patients (−2.45 ± 0.36) compared with GH-treated patients (−1.71 ± 0.68) and patients without GHD (−0.68 ± 0.24; p < 0.0001). No evidence of an increased risk of tumor relapse was observed in association with GH therapy during follow-up. Conclusions: GH replacement significantly improves growth outcomes in medulloblastoma survivors with confirmed GHD without apparent increase in relapse risk when initiated after stable remission. The early identification and multidisciplinary management of GHD are essential components of long-term survivorship care.