Hypothalamic-Pituitary Axis Dysfunction in Survivors of Childhood CNS Tumors: Importance of Systematic Follow-Up and Early Endocrine Consultation

Abstract

The Oncology Grand Rounds series is designed to place original reports published in the Journal into clinical context. A case presentation is followed by a description of diagnostic and management challenges, a review of the relevant literature, and a summary of the authors’ suggested management approaches. The goal of this series is to help readers better understand how to apply the results of key studies, including those published in Journal of Clinical Oncology, to patients seen in their own clinical practice. An 11-year-old male with a history of metastatic tectal plate low-grade glioma who was diagnosed at age 2.8 years transferred his care to the long-term follow-up clinic. He completed treatment with multiagent chemotherapy—carboplatin, vincristine, temozolomide, procarbazine, lomustine, and thioguanine—at age 4.5 years and did not require radiotherapy. At primary diagnosis, he presented with hydrocephalus that required ventriculoperitoneal shunt placement, with a subsequent shunt revision at age 6 years. Residual metastatic tumors in the third and fourth ventricles and in the suprasellar region remained stable for more than 5 years. The patient achieved normal developmental milestones and was not taking medications. He was offered screening for hypothalamic-pituitary axis (HPA) dysfunction because of his suprasellar lesion. His height was at the 25th percentile for chronological age, with decline from the 50th percentile noted during the preceding 18 months ( Fig 1 , point c). Pubertal stage was Tanner 4 for pubic hair and penile size, which contrasted with small testes (4.5 mL). Pubic hair and voice changes were noticed 2 to 3 years before this visit. Plasma testosterone level was consistent with Tanner 4 (255 ng/dL = 8.9 nmol/L). An x-ray of the left hand revealed a notably advanced bone age of 15.5 years. Plasma free T4, thyroid-stimulating hormone (TSH), and 8 am cortisol levels were normal. The patient was referred to the endocrinology clinic where he was diagnosed with growth hormone deficiency and was started on replacement therapy. He reached his final adult height of 144.1 cm at age 13.3 years ( Fig 1 , point d).