A child’s rate of growth in stature is also a sensitive measure of growth hormone status, Darzy notes. “In the absence of other etiologies for growth retardation, the presence of significant growth deviation over a 1-year period (ie, growth velocity below the 25th percentile) … is highly suggestive of clinical growth hormone deficiency.”10

Because growth hormone replacement therapy may not be safe for 1 to 3 years after cancer treatment (the peak-risk period for recurrence, during which time it could facilitate growth of uneradicated tumors), testing usually should not begin within the first year after treatment.10 Thereafter, if growth rate is appropriate for a patient’s pubertal status, Darzy advises that subsequent growth be closely monitored and growth hormone response to ITT be tested annually.10 A normal ITT result 10 years after radiation exposure “usually eliminates the need for further annual testing,” Darzy reports.10 

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Bryant Furlow is a medical journalist based in Albuquerque, New Mexico. 


1. Furlow B. Autoimmune Endocrinopathies: Clinician and Patient Awareness, Communication Are Key. CancerTherapy Advisor. http://www.cancertherapyadvisor.com/autoimmune-endocrinopathies-clinician-and-patient-awareness-communication-are-key/article/345709/. Published May 6, 2014. Accessed July 17, 2014.

2. Sathyapalan T, Dixit S. Radiotherapy-induced hypopituitarism: a review. Expert Rev Anticancer Ther. 2012;12(5):669-683. doi:10.1586/era.12.27.

3. Darzy KH. Radiation-induced hypopituitarism. Curr Opin Endocrinol Diabetes Obes. 2013;20(4):342-353. doi:10.1097/MED.0b013e3283631820.

4. Appelman-Dijkstra NM, Kokshoorn NE, Dekkers OM, et al. Pituitary dysfunction in adult patients after cranial radiotherapy: systematic review and meta-analysis. J Clin Endocrinol Metab. 2011;96(8):2330-2340. doi:10.1210/jc.2011-0306.

5. Bernát L, Hrušák D. Hypothyroidism after radiotherapy of head and neck cancer. J Craniomaxillofac Surg. 2014;42(4):356-361. doi:10.1016/j.jcms.2013.09.009.

6. Lin Z, Wang X, Xie W, et al. Evaluation of clinical hypothyroidism risk due to irradiation of thyroid and pituitary glands in radiotherapy of nasopharyngeal cancer patients. J Med Imaging Radiat Oncol. 2013;57(6):713-718. doi:10.1111/1754-9485.12074.

7. Elson A, Bovi J, Kuar K, et al. Effect of treatment modality on the hypothalamic-pituitary function of patients treated with radiation therapy for pituitary adenomas: hypothalamic dose and endocrine outcomes. Front Oncol. 2014;4:73. doi:10.3389/fonc.2014.00073.

8. Huang S, Wang X, Hu C, Ying H. Hypothalamic-pituitary-thyroid dysfunction induced by intensity-modulated radiotherapy (IMRT) for adult patients with nasopharyngeal carcinoma. Med Oncol. 2013;30(4):710. doi:10.1007/s12032-013-0710-9.

9. Gapstur R, Gross CR, Ness K. Factors associated with sleep-wake disturbances in child and adult survivors of pediatric brain tumors: a review. Oncol Nurs Forum. 2009;36(6):723-731. doi:10.1188/09.ONF.723-731.

10. Darzy KH. Radiation-induced hypopituitarism after cancer therapy: who, how and when to test. Nature Clin Pract Endocrinol Metabol. 2009;5(2):88-99. doi:10.1038/ncpendmet1051.

11. Erridge SC, Conkey DS, Stockton D, et al. Radiotherapy for pituitary adenomas: long-term efficacy and toxicity. Radiother Oncol. 2009;93(3):597-601.

12. Xu Z, Lee Vance M, Schlesinger D, Sheehan JP. Hypopituitarism after stereotactic radiosurgery for pituitary adenomas. Neurosurgery. 2013;72(4):630-637. doi:10.1227/NEU.0b013e3182846e44.

13. Schultz PN. Hypopituitarism in patients with a history of irradiation to the head and neck area: diagnoses and implications for nursing. Oncol Nurs Forum. 1989;16(6):823-826.

14. Warnock C, Siddall J, Freeman J, Greenfield D. Emerging nursing roles for late effects care for children and young adults with cancer. Eur J Oncol Nurs. 2013;17(2):242-249. doi:10.1016/j.ejon.2012.07.009.