Nevertheless, the irradiation of neuroendocrine organs is commonly not considered in radiotherapy planning, and nasopharyngeal cancer treatment guidelines do not specify hypopituitarism as a long-term adverse event following radiotherapy.2 Oncology nurses should be familiar with RIH. Nurses are often responsible for creating late effects treatment summaries, and care and surveillance plans, and communicating risks and plans to patients and pediatric patients’ caregivers or guardians.13 Because of the occurrence of secondary cancers among adult survivors of childhood cancers, oncology nurses are likely to encounter patients in oncology settings who have RIH stemming from treatment during childhood or adolescence. With longer survival times among patients treated for cancer, and a consequently increasing prevalence of patients with late endocrinopathies, nurses and cancer center managers have identified a need to improve nurses’ expertise in endocrine late effects of cancer treatment.14
RIH is irreversible and progressive, causing impaired production of key hormones and resulting in growth disruption, circadian and sleep disturbances, sexual side effects, elevated risk of osteoporosis and obesity, and reduced quality of life.3 Onset can occur soon after radiotherapy ends or years later.
The pituitary gland secretes several hormones, which interact in sometimes complex ways with other endocrine glands, such as the adrenal and thyroid glands, and the ovaries and testicles. RIH-associated pituitary hormone deficiencies can cause downstream target organ deficiencies in the secretion of cortisol, thyroxine, estrogen, and testosterone, with numerous resulting signs and symptoms (See Signs, Symptoms, and associations of hypopituitarism).
|Signs, symptoms, and associations of hypopituitarism|
|The healthy anterior pituitary gland secretes several hormones:|
|Depending on which of these are affected by radiotherapy-induced pituitary dysfunction, symptoms can vary. Onset of symptoms can be gradual. Symptoms are nonspecific and may be subclinical, and go undiagnosed for several years. Symptoms include:|
|Sources: Darzy KH. Radiation-induced hypopituitarism. Curr Opin Endocrinol Diabetes Obes. 2013;20(4):342-353; Hypopituitarism: symptoms. Mayo Clinic Web site. http://www.mayoclinic.org/diseases-conditions/hypopituitarism/basics/symptoms/con-20019292. Accessed July 17, 2014.|
Generally, RIH effects are more pronounced among people treated as children and adolescents than during adulthood; for example, RIH-associated growth hormone deficits can impair a child’s eventual adult height or stature. Up to 41% of all survivors of childhood cancers, and nearly all children who received radiation doses greater than 30 Gy, experience endocrinopathies, of which RIH-associated growth hormone deficiency is the most common form.2 The risk of RIH appears to climb during the decade following irradiation of endocrine organs, making long-term surveillance important in timely diagnosis and clinical intervention.2,3