Late complications in childhood central nervous system tumour survivors

As the treatment of childhood brain tumours has improved, long-term survival has become more common. Cognitive, physical and psychological complications of the tumour and its treatment have been recognized more frequently in long-term survivors. This review highlights new studies on the cognitive and endocrine complications in survivors. Less-common late effects of treatment are also discussed.

Cognitive abnormalities and endocrine dysfunction are the most common complications in long-term survivors. Radiotherapy is the main cause of cognitive dysfunction, but intrathecal methotrexate and surgery are contributory factors. New studies have provided information on the frequency of endocrine complications and risk factors for the development of endocrine disorders. Endocrine complications are uncommon when the tumour has been treated with surgery alone. The risk of developing endocrine dysfunction is increased by radiotherapy, and some studies suggest that chemotherapy has an additional deleterious effect. Primary hypothyroidism may be caused by scattered irradiation from spinal and cranial radiotherapy. Direct involvement of the hypothalamus by the tumour, and hypothalamic damage secondary to surgery or radiotherapy, may cause obesity. Hypothalamic tumours also may be associated with hypersomnolence and other features consistent with narcolepsy. The pathogenesis of hypersomnolence in these patients has not been resolved. Long-term childhood brain-tumour survivors are 40 times more likely to develop a stroke than sibling controls. Superficial siderosis of the central nervous system can develop many years after curative treatment of a cerebellar tumour, but effective treatment for this disorder is not yet available.

An attempt to understand the factors that contribute to the long-term morbidity of childhood brain tumours can lead to changes in treatment that improve the quality of life in survivors. Prevention, early recognition and treatment of these complications are attainable goals.