Brain tumors are the most frequent type of solid neoplasms in children with a recognized 5-year survival rate between 57% and 65%. The survival rate progressively increased in the last few years, due to the improvements in their treatment based on chemotherapy, radiotherapy, and surgery. At the same time, at long term follow-up, clinicians should carefully evaluate comorbidities and long-term sequelae secondary to the disease and its treatment. Growth hormone deficiency (GHD) is an endocrinopathy commonly found among pediatric cancer survivors, with a negative effect on the child's final height and entire metabolism. GH replacement therapy (GHRT), with a synthetic hormone analog, may improve the growth rate and finally adult height, ameliorating the quality of life after cancer treatment. However, in clinical practice, GHRT is adopted with caution for fear of cancer recurrence or the onset of second malignancies. In our review, we perform a focus on the GH structure and function, comparing benefits and risks of GHRT, derived from the analysis of the data currently available in the literature.