Improving Survivorship and Health-related Quality of Life in Patients With Primary Brain Tumours

Background:

Approximately 480 primary, non-pituitary, brain tumours were diagnosed in Ireland each year between 1994 and 2013. Recent developments in treatment have greatly improved survival for younger patients in the 15-54 age range. The Irish National Neurosurgical Centre and the St Luke's Radiation Oncology Centre at Beaumont Hospital and treat approximately 200 patients with brain tumours per year with a combination of surgery, radiotherapy (RT) and chemotherapy with RT being the most commonly used treatment modality. With improved survivorship, the prospect of individuals living for several decades with co-morbidities induced by the tumour itself or surgical and RT treatments, raises new and complex issues for patients and clinicians.

The hypothalamus and pituitary gland in the brain are the key regulators of hormone action. They control several hormone systems including reproductive function (FSH, LH) growth (growth hormone), thyroid (TSH) and adrenal function (ACTH) as well as many other homeostatic mechanisms. It has long been recognised that therapeutic cranial RT to the pituitary gland causes hypothalamic-pituitary dysfunction (hypopituitarism). Traditionally, high-risk groups for post-irradiation hypopituitarism were considered to be patients with pituitary tumours, survivors of childhood cancer and patients who received high-dose RT to treat nasopharyngeal cancers. The potential for cranial radiotherapy to cause significant pituitary dysfunction in adult patients with brain tumours has received little attention. The assumption has been that the hypothalamic-pituitary axis is more resistant in adults than in children to the effect of cranial RT. However, it is likely that the higher doses of RT, used to treat primary brain tumours in adults, causes significant hypothalamic-pituitary dysfunction resulting in hypopituitarism. Preliminary data from the National Pituitary Centre in Beaumont Hospital has revealed that adult patients, treated with cranial radiotherapy for primary, non-pituitary brain tumours, are at risk of hypopituitarism. Approximately 40% of patients had pituitary deficiencies in at least one hormone axis, while 25% of patients had deficiencies in multiple hormone axes. Hypopituitarism confers significant morbidity and increased mortality to patients. At present, adult survivors of brain tumours are referred to the pituitary service for assessment on an ad-hoc basis meaning that many patients with hypopituitarism may go undiagnosed.

In addition to the challenges caused by hypopituitarism, long-term neuropsychological outcomes following a brain tumour cause significant functional impairments and reduced HR-QOL. Patients can present with impairments in specific cognitive domains such as memory and executive functioning or more global systems such as attention as well as significant issues with fatigue. In addition to these primary deficits, patients can also present with significant distress, fluctuant mood and anxiety. Despite the impact of brain tumours can exert, the National Cancer Control Program's National Survivorship Needs Assessment Review (2019) did not identify any studies reporting the needs of adult survivors of brain tumours in Ireland.

There is an urgent need to understand the impact of hypopituitarism and its treatment on HR-QOL and neuropsychological functioning. The proposed study will add to the limited existing literature on the prevalence of hypopituitarism in adult survivors of brain tumours treated with radiotherapy and generate detailed information on deficiency rates for individual pituitary hormones and how these deficiencies emerge over time. This will also be the first study to examine if treatment of radiotherapy-induced hypopituitarism (as part of routine clinical care) is associated with improved HR-QOL and neuropsychological functioning.