News Articles February 2022
Written on 04 February 2022.
How Effective Is Radiation Therapy?
Radiation therapy uses high-energy x-rays to kill cancer cells and abnormal pituitary cells and shrink tumors. Radiation for pituitary tumors these days almost always comes from a radiation source outside the body (external radiation therapy). Radiation therapy may be used if medication/surgery fails to control the tumor. There are several different types of radiation therapy.
- Standard External Beam Radiotherapy uses a radiation source that is nonselective and radiates all cells in the path of the beam; in almost all cases other portions of the brain in the area of the pituitary are in the path of the radiation beam.
- Proton Beam Treatment employs a specific type of radiation in which “protons”, a form of radioactivity, are directed specifically to the pituitary gland. The advantage of this technique is less damage to tissues surrounding the pituitary gland.
- Gamma Knife Irradiation combines standard external beam radiotherapy with a technique that focuses the radiation through many different ports. This treatment tends to do less damage to tissues adjacent to the pituitary gland. Some clinics are using proton beam therapy; laser-guided MR imaged stereotactic intrasellar tumor localization can be used for selected patients with untreated pituitary tumors, incomplete surgical resection, or tumor recurrence.
Are Pituitary Disorders/Diseases Hereditary?
Rarely pituitary adenomas can occur in families. If no other abnormality is associated then this condition is called Familial Isolated Pituitary Adenoma. Most often family members have acromegaly or prolactinoma, sometimes other types of adenomas. Further information is available on www.fipapatients.org.
What Are The Symptoms Of A Pituitary Or Other Neuroendocrine Disorder? (LINKS)
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If a tumor forms in an ACTH secreting pituitary cell, it could result in the overproduction of cortisol (Cushing’s Disease) or the underproduction of cortisol (adrenal insufficiency, often referred to as Secondary Addison’s Disease). Cushing’s is a condition characterized by excessive fat accumulation in central parts of the body (obesity, including a rounded or fat-filled face), diabetes, hypertension, a low serum potassium, thinning and bruising of skin, and osteoporosis.
Symptoms of adrenal insufficiency include dehydration, low blood pressure and sodium level, and excessive weight loss. Primary Addison’s Disease is caused when the adrenal glands fail to respond to directions from the pituitary and hypothalamus.
If the tumor forms in a growth hormone producing cell, it can overproduce growth hormone. Tumors that form from growth hormone producing cells cause two different clinical pictures. If they occur in children before the growth plates in long bones have closed, excessive growth hormone will cause gigantism. If the growth hormone excess occurs during adulthood there is excessive enlargement of the hands, feet, and jaw, as well as soft tissue swelling of many tissues (acromegaly). Acromegaly is associated with an increased probability of developing diabetes mellitus, heart attack, hypertension, and certain types of cancer including malignancy of the colon. Most commonly the facial changes develop subtly and may not be noticed by the patient or his/her family.
To read more about symptoms and other Pituitary Disorders, visit our Disorders section.
For more on the pituitary and prevelence of disorders, visit our One in Five section.
For more on the pituitary and how it works, visit Pituitary Basics.
Are Pituitary Tumors Deadly?
If diagnosed early enough, the prognosis is typically excellent. If not, some tumors can grow into macroadenomas that press on the optic nerves (causing loss of peripheral vision and, in some cases, blindness), the brain (impacting function) and the pituitary (limiting or eliminating hormone production). Large tumors can also invade the cavernous sinuses, which house the carotid arteries, the veins to drain the eyes, and nerves involved in eye movement. Surgery around the cavernous sinuses is difficult and should be performed by an experienced pituitary surgeon. The tumors can also secrete too much of a hormone, causing hypertension, diabetes, mood disorders, sexual dysfunction, infertility, osteoporosis, arthritis, accelerated heart disease and death.
Which Hormones Are Secreted By The Anterior Pituitary?
- Thyroid Stimulating Hormone (TSH) causes the thyroid gland to produce and release thyroid hormones. Thyroid hormone controls the basal metabolic rate and plays an important role in growth and maturation. Thyroid hormones affect almost every organ in the body.
- Growth Hormone (GH) regulates growth and metabolism.
- Adrenocorticotropic Hormone (ACTH) triggers the adrenals to release the hormone cortisol, which regulates carbohydrate, fat, and protein metabolism and blood pressure. The adrenal glands sit above the kidneys and are also responsible for the body’s fight or flight response.
- Luteinizing Hormone (LH) and Follicle Stimulating Hormone (FSH) control the production of sex hormones (estrogen and testosterone) and sperm and egg maturation and release.
- Melanocyte-Stimulating Hormone (MSH) regulates the production of melanin, a dark pigment, by melanocytes in the skin. Increased melanin production produces pigmentation or tanning of the skin; in certain conditions excessive production of melanocyte-stimulating hormone can cause darkening of the skin.
- Prolactin (PRL) stimulates production of breast milk and is necessary for normal milk production during breast feeding.
What If Tumor Is Left Behind After An Attempt At Surgical Removal. Is Radiation Always Required?
If there is a substantial amount of a non-secretory tumor remaining after a transsphenoidal operation, radiation therapy can be used to halt further growth of the residual tumor. There are now a number of different forms of radiation treatment available for pituitary tumors. If only a small amount of tumor remains, it can often be followed with serial MRIs and further therapy deferred until there are signs of regrowth, which may not occur for years. If there is residual tumor after surgery for acromegaly, Cushings disease, or prolactinomas, medical treatments are available to control the excess hormone secretion. These medications, which are typically given under the supervision of an endocrinologist, can sometimes be used instead of, or in addition to, radiation therapy.
How Will We Know If The Entire Tumor Has Been Removed?
For hormone secreting tumors (Cushings, acromegaly, prolactinomas), blood and urine tests in the days or weeks following surgery provide the answer. For non-secreting tumors, pituitary MRI scans are used to determine this. Some centers, such as Massachusetts General Hospital, have a special MRI machine in the operating room, which is used in patients with large tumors, to follow the progress of tumor removal during the operation. Because the surgeon works only from the inside of the tumor, it is sometimes difficult to tell how much tumor remains during the procedure. The intra-operative MRI helps us to see whether there is more to be removed. Tumor in the cavernous sinus can rarely be removed even with the use of the MRI (as noted in Question 4). A postoperative MRI is obtained about six weeks after the surgery. This helps determine whether further therapy is required. If the tumor is a hormone secreting adenoma (prolactinoma, Cushings disease or acromegaly), the endocrinologist will follow your hormone levels postoperatively to determine whether you are cured.
Who Will Take Care Of Me In The Hospital?
At a major pituitary center, such the Neuroendocrine Clinical Center at Massachusetts General Hospital, you will be managed by a team of physicians. This includes your neurosurgeon, a staff neuroendocrinologist and the residents and fellows who work with them. The team will follow you until you can be returned to the care of your local endocrinologist and primary care physician. Endocrine follow-up is very important, to determine whether replacement of any of the hormones controlled by the pituitary (cortisol, thyroxine, estrogen/testosterone, growth hormone or vasopressin) is needed.
How Do You See The Tumor?
The opening through which transsphenoidal surgery is performed is very small, about an inch. Therefore, it is not possible to look with unaided vision at the surgical area or tumor. However, modern technology has developed tools for visualizing the area of the tumor through the small hole. This is done by using a high powered operating microscope, or a fiberoptic endoscope. The operating microscope allows binocular vision with extremely high quality optics. This is very important for tiny tumors, like those responsible for Cushings disease. The endoscope provides a wider field of view, but usually with monocular images as seen on a television screen. At the Massachusetts General Hospital, a direct transnasal approach is used, whether we use the microscope or the endoscope, or both. With the direct transnasal approach, the need for postoperative nasal packing (bandaging in the nose) is minimized, regardless of whether the microscope or endoscope is used.
Are There Other More Serious Complications?
Yes, but they are very rare. There is a very small chance of damaging the carotid arteries which are located on either side of the pituitary. This is a potentially devastating complication which could lead to stroke or death. It occurs very infrequently, when the operation is performed by an expert pituitary surgeon, with an incidence of less than 1/1000 cases. There could also be post-operative bleeding into any residual tumor or into the sella, which could lead to worsening pressure on the optic nerves or chiasm and possible visual loss. This is also a very rare complication, but might require re-operation to remove the blood clot. A spinal fluid leak sometimes occurs because pituitary tumors are separated from the spinal fluid which bathes the brain by a very thin membrane. In order to prevent a spinal fluid leak, the tumor bed is packed with a small piece of abdominal fat taken from a tiny incision made in the abdominal skin. Despite this, spinal fluid leaks occur with an incidence of about 1%. If this happens, there is a risk of infection, called meningitis. If a spinal fluid leak occurs it may require a second operation to patch the leak. The risk of all complications is higher with less experienced surgeons.
Available Now!
The Pituitary Patient Resource Guide Sixth Edition is now available! Be one of the first to have the most up-to-date information. The Pituitary Patient Resource Guide a one of a kind publication intended as an invaluable source of information not only for patients but also their families, physicians, and all health care providers. It contains information on symptoms, proper testing, how to get a diagnosis, and the treatment options that are available. It also includes Pituitary Network Association's patient resource listings for expert medical care.
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