DEBATE: ‘to treat, or not to treat?’ How should a common pituitary tumour variant be treated?
Non-functioning pituitary adenomas (NFPA) are the second most common type of pituitary tumour but within the medical profession there is controversy over whether drug treatment should be given in addition to surgical removal. In this debate, held at the European Congress of Endocrinology in Lisbon, two leading experts in this field will discuss the cases for and against drug treatment for NFPA patients.
Patients with NFPA experience a variety of symptoms caused by the pressure of the tumour on the surrounding tissue, including headaches, visual disturbances, and altered hormone secretion. Surgical removal of the tumour is the first treatment choice. Radiation therapy can be effective in preventing tumour regrowth but is used sparingly due to unpleasant and serious side effects such as headaches, nausea, pituitary damage and injury to the optic nerve. Therefore, 50% of patients experience tumour regrowth and require further surgery and radiotherapy. Some clinicians believe that drug treatments, which can target pituitary tumour cells, should be offered to patients that have significant tumour remnants after surgery to prevent this. However, other professionals would argue that this exposes a large number of people to unnecessary, undefined, long-term treatment, which has not gone through large-scale clinical trials to establish safety or effectiveness.
Dr Yona Greenman, Tel Aviv-Sourasky Medical Center, believes that drug therapy should be offered. Her research team have published a study investigating the use of the drug, cabergoline, in NFPA patients, and report that only 13% of patients experienced tumour regrowth, whilst 42% of those not treated with cabergoline required further surgery and radiotherapy.
Dr Greenman states, “NFPA patients that have tumour remnants should be informed that there is an available medical treatment that can prevent growth of residual tumour and the need for repeated surgery and radiotherapy, which is far more debilitating to patients. Cabergoline was and continues to be the treatment of choice for prolactinomas, the most prevalent pituitary tumour, and its safety record is robust based on decades of treatment in thousands of patients.”
Dr Stylianos Tsagarakis, Evangelismos Athens General Hospital, disagrees and believes that drug treatments are ineffective and that using them to prevent tumour regrowth means a large number of patients undergo unnecessary long-term therapy. He explains that studies supporting their use have been small, with variable dosages and treatment times. The treatments are administered over several years with no defined recommendation on when to stop. A small number of patients do not tolerate the treatment well and can experience dizziness, nausea, sleepiness and low blood pressure. In addition, although the risk appears small, there is some concern that these drugs may increase the risk of developing heart valve disorders but this is unlikely with the lower doses used for pituitary tumours.
Dr Tsagarakis states, “The need for relatively high doses of dopamine-agonists and the long treatment periods required raises some safety concerns. Since only 50% of patients experience tumour regrowth, many would be taking these unproven drugs unnecessarily, which could cause other side effects. When the treatment is actually needed, it is not very effective and unfortunately we cannot yet accurately predict the risk of tumour recurrence.”
Both Dr Greenman and Dr Tsagarakis feel strongly that this issue should be highlighted to medical professionals and patients, and that well designed clinical trials are needed to settle the debate.
Notes for Editors
The debate “Is there a role for medical therapy for non- functioning pituitary adenomas?” was held at the European Congress of Endocrinology at the Centro de Congressos de Lisboa, in Lisbon, Portugal.
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