Target Gland Dysfunction Following External Cranial Radiation for Extrasellar Tumours

Area of Science:

• Endocrinology
• Radiation Oncology
• Oncology

Background:

• Pituitary gland diseases involve hormone imbalances affecting target glands like the thyroid, adrenal, and gonads.
• Hypothalamo-pituitary axis dysfunction can occur after radiation therapy for tumors when the radiation field includes this area.
• This study investigates target gland dysfunction following extracranial radiation for extrasellar tumors.

Purpose of the Study:

• To assess the prevalence of target gland dysfunction after extracranial radiation for extrasellar tumors.
• To determine the relationship between radiation dose, duration post-radiotherapy, and the incidence of target gland dysfunction.
• To identify the specific types and frequencies of endocrine deficiencies (hypogonadism, hypoadrenalism, hypothyroidism).

Main Methods:

• Evaluated 96 patients 12 months post-cranial radiation for extrasellar tumors.
• Measured basal hormone levels including triiodothyronine (T3), thyroxine (T4), thyrotropin stimulating hormone (TSH), and cortisol.
• Conducted pooled sample analysis for luteinizing hormone (LH) and follicle-stimulating hormone (FSH), and performed insulin tolerance tests for stimulated cortisol.

Main Results:

• 75% of patients exhibited target gland dysfunction.
• Hypogonadism was most prevalent (53%), affecting 36% of males and 100% of females.
• Hypoadrenalism occurred in 46% and hypothyroidism in 13% of patients, with dysfunction increasing with radiation dose and time post-treatment.

Conclusions:

• Target gland dysfunction is a common sequela of extracranial radiation for extrasellar tumors.
• Hypogonadism, hypoadrenalism, and hypothyroidism are the primary endocrine deficits observed.
• The development of dysfunction is associated with patient age, radiation dose, and time elapsed since radiotherapy.