Endocrine Abstracts

Endocrine late effects following cancer therapy are increasingly recognized. Due to the radio-sensitivity of the thyroid gland both long-term effects on thyroid function and growth have been described. This includes problems of thyroid growth and function. Particularly the development of secondary neoplasms of the thyroid is greatly increased some 10 to 30 years following irradiation. This affects predominantly children before and during puberty. The longitudinal use of thyroid ultrasound greatly improves the diagnosis of thyroid carcinomas in this high risk group. Thyroid function may be altered by direct irradiation to the gland but also indirectly by radiation therapy which includes the pituitary. In a recent study we could demonstrate that follow-up particularly the latter group by expert endocrinologists as compared to GPs results in a substantial improvement in the diagnosis of hypothyroidism. Chemotherapy is much less likely to affect the thyroid. However, recent data on the use of new receptor tyrosine kinase (RTK) inhibitors suggest a substantial risk of hypothyroidism which is usually reversed when RTK inhibitors are stopped. Finally, antibody treatment with CTLA4 inhibitors as recently introduced in the treatment of melanoma may result in pituitary problems which may lead to central hypothyroidism. In summary, as long-term problems of thyroid function and growth following treatment of cancer are not infrequent, cancer survivors should be carefully monitored for thyroid problems.

Declaration of interest: There is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported.

Funding: No specific grant from any funding agency in the public, commercial or not-for-profit sector.