Pituitary Cancer

What is Pituitary Cancer?

The pituitary gland is a small organ situated in a hollow space within the sphenoid bone, a shape resembling a butterfly at the base of the skull. The pituitary gland is split into an anterior (front) and posterior (back) portion. The front part consists of glandular tissue, while the back part is made up of nerve tissue. This gland is linked to another brain region, the hypothalamus, through a structure called the pituitary stalk, which facilitates the transfer of hormones and nerve signals.

The front part of the pituitary gland is controlled by hormones from the hypothalamus, while the hormones of the back part are produced by the hypothalamus itself and are then stored in the pituitary gland until they are needed.

Around 15% of all tumors that occur within the skull originate from the anterior part of the pituitary gland. These pituitary tumors are usually non-cancerous, or benign. However, in exceptional cases, pituitary tumors can spread to other parts of the body, at which point they are referred to as pituitary carcinomas, a type of cancer. It’s important to note that pituitary carcinoma is a different condition from cancers that spread from other organs, like the lung or breast, into the pituitary gland, which are far less common .

What we aim to do here is provide a clear, comprehensive look at pituitary cancer. This includes discussing general rates and patterns of occurrence, symptoms you might experience, how doctors diagnose it, methods through which we can predict its behaviour, current and emerging treatment methods, and what the prognosis or expected outcome might be.

What Causes Pituitary Cancer?

The exact cause of pituitary gland tumors is still not completely understood, but it’s believed to be linked to genetic changes or abnormalities. Scientists are currently doing research to better understand the molecular processes that drive the behavior of pituitary tumors. Some studies suggest that changes in the way genes are regulated and expressed, through processes such as methylation, histone regulation, and changes in certain types of RNA, may be associated with cancer.

In addition, some pituitary tumors have been found to be linked to specific genetic mutations (such as MEN1, AIP, GPR101). These tumors are often more resistant or invasive.

Certain inherited conditions can also increase the risk of developing pituitary tumors. For example, a condition called multiple endocrine neoplasias-1 syndrome is often linked to a type of pituitary tumor called an adenoma. At this time, no environmental factors or lifestyle habits have been directly connected to the cause of pituitary tumors, so there are no specific recommendations to prevent them.

Risk Factors and Frequency for Pituitary Cancer

Pituitary carcinoma, a type of tumor in the pituitary gland, is pretty rare. Around only one in a million people might have it, and it makes up less than 0.01% of all detected tumors in the front part of the pituitary gland. These carcinomas most commonly come from working parts of the pituitary gland, specifically from areas known as lactotrophs and corticotrophs.

These two types each make up about a third of all pituitary carcinoma cases.
People are generally diagnosed with this type of cancer around the age of 44 to 45.
On average, it takes about 5 to 7.5 years from diagnosis to the first metastasis or spread of the cancer.
In some cases, a non-functioning pituitary tumor can switch to a functioning tumor, meaning it starts producing hormones. This is usually seen in cases where benign tumors, known as pituitary adenomas, have progressed to become carcinomas.

Signs and Symptoms of Pituitary Cancer

Pituitary tumors are divided into two types. Some tumors produce excessive hormones (functional or secreting), which can result in various symptoms depending on the hormone involved. On the other hand, non-functional tumors (those that do not secrete hormones) often do not cause any symptoms until they grow large enough to interfere with nearby structures in the brain. In some cases, these tumors are found accidentally during scans for other health concerns. If someone with a pituitary tumor experiences neck or back pain, it might mean the cancer has spread to the spine (pituitary carcinoma).

Pituitary tumors can put pressure on several structures within the brain and lead to specific symptoms. For example, if a tumor squeezes the optic chiasm, it might cause vision problems like bitemporal hemianopsia or decreased visual acuity. If the tumor affects the cavernous sinus, a channel within the skull housing several critical structures, it can cause symptoms such as droopy eyelids, double vision, or facial pain. In rare cases, the tumors can block the flow of brain fluids and result in conditions such as hydrocephalus. When large tumors known as macroadenomas grow, they can cause general symptoms like headaches. Occasionally, some invasive tumors might cause leakage of cerebrospinal fluid from the nose.

Excess production of prolactin can cause sexual dysfunction in men, while in women, it can lead to conditions like amenorrhea-galactorrhea syndrome (absence of periods and breast milk discharge).
Excessive growth hormone can cause gigantism in children before puberty, while in adults, it results in a condition called acromegaly.
If there is too much adrenocorticotropic hormone, it leads to Cushing’s disease. Symptoms can include high blood pressure, purple stretch marks on the skin, reduced libido, thin skin that bruises easily, depression, muscle wasting, and weight gain with fat accumulation in particular areas of the body.
Excess production of thyroid-stimulating hormone can lead to secondary hyperthyroidism, causing symptoms such as sweating, heat intolerance, diarrhea, and weight loss.
Overproduction of follicle-stimulating hormone and/or luteinizing hormone usually does not result in a clinical syndrome. However, in women of reproductive age, it can cause ovarian hyperstimulation, leading to ovarian cysts, amenorrhea (absence of periods), and galactorrhea (breast milk discharge).

Large pituitary tumors might compress the normal pituitary gland, leading to the underproduction of some hormones. Starting from most to least sensitive to compression, these hormones are growth hormone, gonadotropins, thyroid-stimulating hormone, adrenocorticotropic hormone, and prolactin. Pituitary apoplexy, a condition involving the rapid expansion of a pituitary tumor due to bleeding or necrosis, usually presents with a headache, neurological deficit, and/or hormonal deficit. Unlike other pituitary tumors, it might also result in ophthalmoplegia (eye muscle weakness).

Testing for Pituitary Cancer

When it comes to testing for hormonal issues, doctors usually use both blood and urine tests. If you’re having certain symptoms, these tests could involve checking specific hormone levels. But often, a range of different hormones will be checked, especially if there’s an unexpected or non-functioning growth. The main purpose of these tests is to rule out tumors that are producing too many hormones. Usually, these tests will measure levels of hormones like prolactin and insulin-like growth factor (IGF-1). Doctors also reserve tests for cortisol levels, a hormone that helps manage stress, for patients showing signs of Cushing disease.

There are certain types of tumors that can cause the pituitary gland to produce too few hormones, a condition called hyposecretion. These could involve one or more hormones being affected. If these types of tumors are suspected, doctors will check levels of multiple hormones including thyroid-stimulating hormone (TSH), follicle-stimulating hormone (FSH), luteinizing hormone (LH), free T4, total testosterone in men, and cortisol. If there’s a condition called hypogonadotropic hypogonadism, where the body isn’t producing adequate sex hormones, doctors will use magnetic resonance imaging (MRI) to check for a pituitary tumor as the possible cause. Additional confirmatory tests associated with the specific hormone involved would follow after these initial lab tests.

In terms of imaging, MRI scans focusing on the pituitary gland, located at the base of the brain, are the primary method. These tumors can be labeled based on size: ‘macroadenomas’ if they’re larger than a centimeter or ‘microadenomas’ if they’re smaller than one centimeter. A computed tomography angiography (CTA) scan of the head might be used to help plan for surgery by allowing doctors to see the nearby blood vessels, like the internal carotid artery. If there’s concern about pituitary cancer, the diagnosis can be confirmed if the cancer has been found to have spread to other parts of the body on scans, usually checked through spine MRIs.

Treatment Options for Pituitary Cancer

For pituitary tumors, surgery is commonly used. Nearly 80.5% of patients with pituitary cancer have undergone surgery at least twice, and 27.9% have had four or more surgeries. This procedure, known as surgical debulking, aims to reduce the mass of the tumor. It can be beneficial if the tumor is pressing against nearby structures in the brain, such as the optic pathway, third ventricle, or brainstem.

Other treatment options include radiotherapy, which has been used in about 42.9% of pituitary cancer patients. The exact method of radiotherapy is determined on a case-by-case basis in consultation with specialists. The goal of this treatment is to reduce the size of the tumor and minimize its secretion of hormones. However, the effect of radiotherapy often takes time, and it’s generally considered as part of a combined treatment approach.

Chemotherapy is another treatment option. Temozolomide, an oral medication that interferes with DNA, is usually the first choice for chemotherapy. Temozolomide works by causing irreversible DNA damage, which can impede the growth of the tumor. Though it’s the preferred drug, only a small percentage of patients show complete or partial response to Temozolomide. It has been found to be more effective when used in conjunction with radiotherapy, especially for clinically functioning pituitary tumors and tumors displaying low expression of a certain protein, MGMT.

For tumors that are not responding to Temozolomide, there are currently no other proven treatments available. So, it’s essential to maximize the effectiveness of Temozolomide for as long as possible. In some cases, doctors may start chemotherapy earlier in the treatment plan.

Medications can also be used to control excess hormone production caused by pituitary tumors. For example, dopamine agonists like cabergoline can be used in high doses for lactotroph tumors. For patients with excessive cortisol levels, medications like metyrapone or ketoconazole can be crucial to avoid complications. And for somatotrophic tumors, medications like octreotide, pegvisomant, or dopamine agonists can be used.

Several potential future treatments are currently being studied. These include immunotherapy and targeted therapies like bevacizumab (which targets a protein involved in blood vessel growth), everolimus (which interferes with a protein involved in cell growth and division), and various tyrosine kinase inhibitors.

The SATCHMO mnemonic is a tool used by doctors to remember different conditions that could potentially be causing a pituitary tumor, as seen in scans or imaging. This nickname, inspired by famous musician Louis Armstrong, represents various conditions:

S: Sarcoidosis or sellar tumor (like a pituitary adenoma or carcinoma)
A: Aneurysm, usually superior hypophyseal
T: Teratoma, tuberculosis, or other granulomatous diseases
C: Craniopharyngioma, chordoma, or cleft cyst (Rathke’s)
H: Hypothalamic glioma, hamartoma, or histiocytosis
M: Meningioma, or cancer spreading from other areas (metastasis)
O: Optic nerve glioma

The doctors use these signs to rule out possible causes and identify the source of the pituitary tumor.

What to expect with Pituitary Cancer

The overall outlook for benign, or non-cancerous, pituitary tumors is generally good when compared to other brain or hormonal tumors. About 82% of patients live for at least five years after being diagnosed.

However, the prognosis is not as positive for pituitary carcinoma, which is a form of cancer. On average, patients with pituitary carcinoma live less than four years once it has spread to other parts of the body.

Possible Complications When Diagnosed with Pituitary Cancer

: One of the worst complications from a pituitary tumor is blindness. This can occur if the tumor pushes against certain nerves related to sight, leading to partial or full loss of vision. Some tumors may not initially have any impact on vision, but could cause rapid vision loss as they grow.

In larger tumors, also known as macroadenomas, diabetes insipidus can occur. This is due to a shortage of the hormone vasopressin, which controls the body’s water levels. The result can be extreme thirst and excessive urination.

Pituitary apoplexy is a serious condition involving the sudden bleeding or hemorrhage in the pituitary gland. It’s a medical emergency that can trigger a severe headache, paralysis of eye muscles, and visual disturbances.

Repeated surgeries can lead to more complications, including a condition called hydrocephalus which requires the placement of a shunt within the brain. To reduce risks related to surgeries, it’s best for the procedure to be performed by an expert neurosurgeon who has a lot of experience with pituitary tumors.

Radiation therapy for pituitary adenomas has been linked in a few cases to the development of severe types of cancer many years later. However, there’s ongoing debate about whether the radiation treatment was actually the cause.

Possible complications after surgery include infection, leakage of cerebrospinal fluid (CSF), damage to the structures within the sinus cavity, and rarely, rupture of the carotid artery either during or after surgery.

Possible Complications:

Blindness
Diabetes insipidus
Pituitary apoplexy
Hydrocephalus
Infection (meningitis or pituitary abscess)
CSF leak
Damage to sinus cavity structures
Rupture of the carotid artery

Preventing Pituitary Cancer

The pituitary gland is a small organ in the brain that helps regulate your body’s hormones. Sometimes, tumors can form on this gland and cause symptoms by affecting nearby structures, like the parts of the brain related to vision, or by upsetting the gland’s normal activities. This could cause changes in vision, irregular menstruation cycles, milky discharge from breasts in women, or problems with erections or lowered sex drive in men. If the tumor causes an overproduction of steroid hormones, it may lead to symptoms like weight gain, weak bones, and high blood pressure.

Other related conditions could involve an abnormal growth of your hands or head due to different types of hormones. Some patients might also experience general symptoms like headaches. Pituitary cancer, which is very rare, could arise from the pituitary gland itself or from another part of the body and spread to the gland, which is known as pituitary carcinoma. Symptoms of pituitary carcinoma could involve neck or back pain if the cancer has spread to the spine.

Various methods are used to diagnose these conditions, and they usually involve lab tests and imaging techniques like x-rays. Your doctor will determine which tests are necessary based on your specific situation. Treatment often includes surgery and may also involve additional treatments like radiosurgery, which is a type of targeted radiation therapy, or drugs to boost the body’s immune system and/or kill the cancer cells.

Frequently asked questions

Pituitary cancer is a type of cancer that originates from the anterior part of the pituitary gland. It is a rare condition, with only around 15% of all tumors within the skull being pituitary tumors. Most pituitary tumors are non-cancerous, but in exceptional cases, they can spread to other parts of the body and become pituitary carcinomas.

Pituitary carcinoma is pretty rare, with only one in a million people having it and making up less than 0.01% of all detected tumors in the front part of the pituitary gland.

Signs and symptoms of Pituitary Cancer include: - Excessive hormone production: Some pituitary tumors produce excessive hormones, leading to various symptoms depending on the hormone involved. For example, excess production of prolactin can cause sexual dysfunction in men and conditions like amenorrhea-galactorrhea syndrome in women. Excessive growth hormone can cause gigantism in children and acromegaly in adults. If there is too much adrenocorticotropic hormone, it leads to Cushing's disease, which can cause high blood pressure, purple stretch marks, reduced libido, thin skin, depression, muscle wasting, and weight gain with fat accumulation in specific areas of the body. Excess production of thyroid-stimulating hormone can lead to secondary hyperthyroidism, causing symptoms such as sweating, heat intolerance, diarrhea, and weight loss. Overproduction of follicle-stimulating hormone and/or luteinizing hormone usually does not result in a clinical syndrome, but in women of reproductive age, it can cause ovarian hyperstimulation, leading to ovarian cysts, amenorrhea, and galactorrhea. - Compression of nearby structures: Pituitary tumors can put pressure on several structures within the brain, leading to specific symptoms. For example, if a tumor squeezes the optic chiasm, it might cause vision problems like bitemporal hemianopsia or decreased visual acuity. If the tumor affects the cavernous sinus, it can cause symptoms such as droopy eyelids, double vision, or facial pain. In rare cases, the tumors can block the flow of brain fluids and result in conditions such as hydrocephalus. Large tumors known as macroadenomas can cause general symptoms like headaches. Occasionally, some invasive tumors might cause leakage of cerebrospinal fluid from the nose. - Neck or back pain: If someone with a pituitary tumor experiences neck or back pain, it might mean the cancer has spread to the spine (pituitary carcinoma). - Pituitary apoplexy: Pituitary apoplexy is a condition involving the rapid expansion of a pituitary tumor due to bleeding or necrosis. It usually presents with a headache, neurological deficit, and/or hormonal deficit. Unlike other pituitary tumors, it might also result in ophthalmoplegia (eye muscle weakness). It's important to note that not all pituitary tumors cause symptoms, and some may be found accidentally during scans for other health concerns.

The exact cause of pituitary gland tumors, including pituitary cancer, is still not completely understood. It is believed to be linked to genetic changes or abnormalities, and some tumors have been found to be linked to specific genetic mutations. Certain inherited conditions can also increase the risk of developing pituitary tumors. However, no specific environmental factors or lifestyle habits have been directly connected to the cause of pituitary tumors.

The doctor needs to rule out the following conditions when diagnosing Pituitary Cancer: - Sarcoidosis or sellar tumor (like a pituitary adenoma or carcinoma) - Aneurysm, usually superior hypophyseal - Teratoma, tuberculosis, or other granulomatous diseases - Craniopharyngioma, chordoma, or cleft cyst (Rathke's) - Hypothalamic glioma, hamartoma, or histiocytosis - Meningioma, or cancer spreading from other areas (metastasis) - Optic nerve glioma

The types of tests needed for Pituitary Cancer include: - Blood tests to measure hormone levels, such as prolactin, insulin-like growth factor (IGF-1), cortisol, thyroid-stimulating hormone (TSH), follicle-stimulating hormone (FSH), luteinizing hormone (LH), free T4, and total testosterone in men. - Urine tests to check for specific hormone levels. - Magnetic resonance imaging (MRI) scans of the pituitary gland to check for tumors. - Computed tomography angiography (CTA) scan of the head to visualize nearby blood vessels. - Spine MRIs to check for spread of cancer to other parts of the body.

Pituitary cancer can be treated through various methods, including surgery, radiotherapy, chemotherapy, and medication. Surgery, known as surgical debulking, aims to reduce the size of the tumor and is commonly used. Radiotherapy is used to minimize the tumor's size and hormone secretion, while chemotherapy, specifically using the drug Temozolomide, can impede tumor growth by causing DNA damage. Medications can also be used to control excess hormone production caused by pituitary tumors. Additionally, potential future treatments being studied include immunotherapy and targeted therapies.

The side effects when treating Pituitary Cancer can include: - Blindness: If the tumor presses against certain nerves related to sight, it can lead to partial or full loss of vision. - Diabetes insipidus: This occurs in larger tumors and is caused by a shortage of the hormone vasopressin, resulting in extreme thirst and excessive urination. - Pituitary apoplexy: A serious condition involving sudden bleeding or hemorrhage in the pituitary gland, which can cause a severe headache, paralysis of eye muscles, and visual disturbances. - Hydrocephalus: Repeated surgeries can lead to this condition, which requires the placement of a shunt within the brain. - Infection (meningitis or pituitary abscess): Possible complications after surgery can include infection. - CSF leak: Leakage of cerebrospinal fluid can occur after surgery. - Damage to sinus cavity structures: Surgery can potentially cause damage to the structures within the sinus cavity. - Rupture of the carotid artery: Rarely, the carotid artery can rupture either during or after surgery.

On average, patients with pituitary carcinoma live less than four years once it has spread to other parts of the body.

An endocrinologist or a neurosurgeon.

Brain and Spine Cancer Cancer Pituitary Hormone Oversecretion Pituitary Hormone Undersecretion Pituitary Tumor