Pituitary deficiency after brain radiation therapy.

Area of Science:

• Endocrinology
• Radiation Oncology

Background:

• Brain radiotherapy can lead to pituitary deficiency, affecting adult health and quality of life.
• Hormonal consequences are well-documented in children but less studied in adults.

Observation:

• Hormonal deficiencies depend on radiation dose to the pituitary-hypothalamic region.
• Growth hormone (GH) deficiency is the first and most common, affecting 90% of patients within 10 years.
• Other anterior pituitary functions are affected later; hypothalamic damage can cause mild hyperprolactinemia, but diabetes insipidus is not observed.

Findings:

• The insulin tolerance test is the gold standard for diagnosing GH and ACTH deficiencies, even with normal initial screening tests.
• Thyroid deficiency may occur with cranio-spinal irradiation, necessitating regular ultrasounds to screen for thyroid cancer.
• Gonadotrophic function can be affected, leading to precocious puberty with low doses or delayed puberty/deficiency with higher doses.

Implications:

• Understanding the timing and sequence of hormonal deficiencies is crucial for tailored patient monitoring.
• Prospective studies are needed to establish precise monitoring protocols for adult patients post-radiotherapy.
• Combined radio- and chemotherapy can cause complex deficiencies requiring careful diagnosis.