The impact of cancer treatment on pituitary function
Improvements in cancer therapy have led to increasing numbers of patients surviving complex conditions. A multidisciplinary approach using new treatment modalities allow more aggressive therapy and a greater risk in the long-term to pituitary function. Damage to the hypothalamic pituitary axis has traditionally resulted from the underlying lesion, surgical intervention and radiotherapy. Traditional chemotherapeutic agents have not been implicated. The effect radiation has upon a tissue is determined by the radiation dose, fractionation schedule and sensitivity of that tissue to radiation. The relative insensitivity of neural tissue to radiation results in a slowly evolving picture of pituitary dysfunction with pituitary hormone deficiencies occurring in a reasonably predictable fashion. The rapidity of onset of hormone deficits may be influenced by the presence of pathology within the hypothalamus or pituitary at diagnosis. Recent developments in cancer therapy include the use of biological agents, for example Alemtuzumab used in the management of leukaemia and Ipilimumab used in metastatic melanoma. These agents alter immune function and can cause autoimmune disease including endocrinopathy. Hypophysitis is a recognised complication of these agents causing adrenal insufficiency in patients who are already sick and at risk of Addisonian crises. Many patients treated for intracranial malignancy and for complications such as graft vs host disease following stem cell transplantation receive glucocorticoid therapy for protracted periods of time, causing suppression of the hypothalamic-pituitary axis. The resulting hypoadrenalism makes it difficult to withdraw steroids causing significant morbidity. Patients treated for malignant disease who are at risk of hypothalamic-pituitary dysfunction require monitoring in a centre with expertise in managing pituitary disease and the other complications that can arise from cancer treatment.
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.