Endocrine outcome in long-term survivors of low-grade hypothalamic/chiasmatic glioma

OBJECTIVE

We have evaluated the frequency of endocrine abnormalities in a large group of patients with hypothalamic/chiasmatic glioma (H/CG) and its correlation with the different forms of therapy.

DESIGN

Descriptive retrospective study using case note review analysis.

PATIENTS

The records of 68 children who survived H/CG were analysed. One third had neurofibromatosis. The mean age at tumour presentation was 5 years. The median time of follow-up was 3.6 years. Thirty-eight children received cranial radiation, of whom 17 also had surgery. Surgery was performed in a total of 24 patients. Fifteen patients received only chemotherapy. Eight children, all with neurofibromatosis, received no specific tumour treatment.

MEASUREMENTS

Endocrine dysfunction was determined by clinical manifestations and biochemical evaluation of hypothalamic-pituitary function.

RESULTS

Endocrine dysfunction occurred in 42% of the children. The most common disorder was GH deficiency (GHD). Of 50 children evaluated, 15 of the 19 with GHD received cranial irradiation (P < 0.05). HOwever, 15 children treated with more than 15 Gy grew normally. Precocious puberty was diagnosed in 11 patients. Nine patients, all treated with cranial irradiation, developed hypogonadotrophic hypogonadism. Of the 14 patients with hypothyroidism, 10 had surgery (P < 0.005). Hypoadrenalism and diabetes insipidus each occurred in eight patients, and were associated with multiple endocrine deficiencies and surgery. Endocrine deficiencies occurred in children with neurofibromatosis as frequently as children without neurofibromatosis but only when comparing those treated with cranial irradiation or surgery.

CONCLUSIONS

Nearly all studies assessing the patients with different tumour therapy evaluate patients wit different tumour types. This study investigates a specific and large population of patients with H/CG and correlates the different form of treatment with the endocrine outcome. Precocious puberty, in children with this tumour, is probably due to tumour location rather than oncological therapy. Conversely, although endocrine deficiencies can be a result of tumour location, the major causes of endocrine abnormalities were field irradiation and tumour surgery. A notable finding not previously reported is that endocrine dysfunction occurs less often in neurofibromatosis patients treated conservatively. Furthermore, this study documents that a significant number of young children grew normally despite receiving brain irradiation of greater than 45 Gy.

Long-term outcome of hypothalamic/chiasmatic astrocytomas in children treated with conservative surgery

The feasibility of radical surgery for astrocytomas of the optic chiasm/hypothalamus has been reported by several groups. Such surgery carries significant risks, however, including permanent damage to the pituitary gland, optic apparatus, hypothalamic structures, and carotid arteries. The benefits of radical surgery, both in terms of efficacy and toxicity, should, therefore, be evaluated against standard therapy, as is usually done for new chemotherapeutic protocols. To this end, a retrospective review was performed of 33 patients treated at Children's Hospital of Philadelphia between 1976 and 1991 who met criteria that would have made them eligible for radical surgery in many centers today, but were treated with either no surgery or conservative surgery (< 50% resection) or biopsy followed by adjuvant therapy with local radiation therapy (29 patients) and/or chemotherapy with actinomycin-D and vincristine (18 patients). The review encompassed all children with a globular enhancing mass of at least 2 cm in the hypothalamic/chiasmatic region, no evidence of optic nerve involvement or involvement of the optic radiations by computerized tomography or magnetic resonance imaging, and follow up of at least 3 years. All but one patient had tissue confirmation of a low-grade or pilocytic astrocytoma. Thirteen of the patients were 2 years of age or younger at diagnosis. Five individuals died: three of tumor progression, one of acute shunt malfunction, and one of intercurrent infection. The remaining 28 were alive at last follow up, a mean of 10.9 years from diagnosis. Twenty-three surviving patients have functional vision in at least one eye, 12 require no endocrine replacement, and 16 are in or have completed schooling with regular academic requirements. If radical surgery is to become standard care for children with low-grade astrocytomas of the hypothalamic/chiasmatic region, long-term survival and functional outcome will have to equal or surpass those of historical controls who were treated conservatively.