Pituitary Dysfunction in Patients with Intracranial Germ Cell Tumors Treated with Radiotherapy

Objective: To evaluate the endocrine abnormalities in intracranial germ cell tumors (iGCTs) treated with radio-therapy (RT), and to discuss the effects of RT on pituitary functions.

Methods: Seventy-seven patients diagnosed with iGCTs who had received RT and endocrine follow-up in Huashan Hospital between January 2010 and July 2017 were retrospectively analyzed, consisting of 49 germinomas and 28 NGGCTs. The median follow-up period was 50.0 months. Fifty-one patients had radiologically proved suprasellar/sellar lesions.

Results: The male to female ratio was 62/15. The median endocrine follow-up period was 19 (4, 42) months. The median age at the last endocrine visit was 18 (16, 20) years old. The 5-year overall and recurrence-free survival were both 98.7%. The overall prevalence of central adrenal insufficiency (CAI), central hypothyroidism (CHT), central hypogonadism (CHG), hyperprolactinemia, and central diabetes insipidus (CDI) was 57.3%, 56%, 56.6%, 35.3%, and 52.1%, respectively, after RT. Patients having suprasellar/sellar lesions showed significantly higher post-therapeutic prevalence of hypopituitarism than those who didn't. Compared to that before RT, CAI, CHT, and CHG weren't significantly improved while the levels of prolactin and the prevalence of CDI declined significantly (P =.03 and.001). The radiation doses to pituitary and hypothalamus between those with and without CAI, CHT, and CHG weren't significantly different.

Conclusion: The prevalence of hypopituitarism was high in iGCTs, especially in those with suprasellar/sellar involvement. The levels of prolactin and the prevalence of CDI declined significantly after RT. The hypopituitarism in iGCTs was mainly induced by tumor effects, and RT showed no additional damage to pituitary functions in our study.

Abbreviations: AFP = alpha-fetoprotein; CAI = central adrenal insufficiency; CDI = central diabetes insipidus; CHG = central hypogonadism; CHT = central hypothyroidism; CT = computed tomography; DA = dopamine; GH = growth hormone; βHCG = beta-human chorionic gonadotropin; HPA = hypothalamus-pituitary-adrenal; HPG = hypothalamus-pituitary-gonadal; HPL = hyperprolactinemia; HPT = hypothalamus-pituitary-thyroid; iGCT = intracranial germ cell tumor; IGF-1 = insulin-like growth factor 1; NGGCT = nongerminomatous germ cell tumors; OS = overall survival; PFS = progression-free survival; PRL = hypothalamus-pituitary-prolactin; RT = radiotherapy.