Pituitary Gland Cancer

Clinical picture

When a spontaneous unbridled cell growth occurs in the pituitary gland, it is called a pituitary gland tumour. Though almost always benign in nature, these tumours can lead to serious problems due to their location and the pressure they exert on certain parts of the brain, thus impairing functionality.

The pituitary gland is a gland at the base of the brain that produces several hormones. The gland is divided into two lobes: the anterior pituitary (or adenohypophysis) and the posterior pituitary (or neurohypophysis). Hormones secreted from the pituitary gland help in controlling growth, blood pressure, energy management, all functions of the sex organs, thyroid glands and metabolism as well as some aspects of pregnancy, childbirth, nursing, water/salt concentration in the kidneys, temperature regulation and pain relief.

There are two tumour types, functioning and non-functioning. A non-functioning tumour does not produce hormones, whereas a functioning one does. It is a very rare cancer: during 2015 only one patient in Belgium was diagnosed with a pituitary gland tumour.

Symptoms

Patients with a non-functioning tumour can present the following symptoms:

Problems with sight: the pituitary gland is located close to the optical nerve.
Lowered hormone production:
- Growth hormone: in children this can lead to a lower growth rate or belated puberty.
- Thyroid stimulating hormone (TSH): a decrease in the production of TSH impairs the working of the thyroid glands, leading to fatigue, weight gain and low energy levels.
- Adrenocorticotrophic hormone (ACTH): this hormone is involved in the production of cortisol by the adrenal glands. A shortage of cortisol leads to a condition known as Addison’s Disease, which can lead to fatigue, low blood pressure and vertigo.
- Sex hormones: a lower production of sex hormones can lead to reduced fertility.

Patients with a functioning tumour can present the following symptoms that are all caused by excess hormone production.

Prolactin: a tumour that produces too much prolactin is known as a prolactinoma. It can lead to spontaneous lactation in both men and women, but it can also impair fertility.
Growth hormone: when too much growth hormone is released, it is known as acromegaly. This can lead to growth of the skull, jaws, hands and feet. The patient also develops more sweat glands, a thickened palate and will feel constant fatigue.
ACTH: an excess of ACTH can lead to Cushing’s Disease. Its main symptoms are weight gain, bloating in the face, high blood pressure and elevated blood sugar levels, osteoporosis, fatigue and symptoms of a psychological nature.
TSH: patients that have a tumour that leads to excess TSH production have symptoms such as weight gain, cardiac arrhythmia, nervosity, short-temperedness, excess persperation and changes in faeces.

Cause

No cause for pituitary gland cancer has been identified so far, nor are there specific risk-inducing factors.

Diagnosis

A GP who suspects their patient may be suffering from a pituitary gland condition may order blood tests and urine tests. He will also examine the patient’s eyes. In case the GP suspects cancer, the patient will be referred to an endocrinologist, who may order an MRI scan of the brain.

Treatment

A pituitary gland cancer can be treated with surgery, radiotherapy or medication. Often, however, the tumour remains untreated.

Medication can be given for two different reasons. One type of medicine makes the tumour shrink in size. Other medicines address the effects of under- or overproduction of hormones and the symptoms associated. Targeted therapy with mTOR, VEGF, kinase, PD-L1 and CTLA-4 inhibitors are under current investigation.

Radiotherapy is suggested when the effects of the medication are insufficient or when surgery brings too much of a risk, or when the tumour returns.