Endocrinology oncology

Also known as: Endocrine oncology

Definition:Endocrinology oncology is the treatment of cancers affecting the endocrine organs, which are organs that produce hormones. Endocrine organs include the thyroid, adrenal glands, endocrine pancreas, and pituitary gland.

Cancers treated:Thyroid tumors (including papillary, follicular, medullary, anaplastic, and mixed papillary/follicular tumors); parathyroid tumors; adrenal tumors (including pheochromocytoma and incidentally discovered adrenal masses); tumors of the endocrine pancreas (for example, insulinoma, gastrinoma, glucagonoma); tumors of the pituitary gland

Training and certification: Most doctors who treat patients with endocrine cancers are not specifically trained through endocrinology oncology residencies and fellowships. Instead, they may have completed surgical residencies, either in general surgery or in oncology or endocrine surgery. The average length of a surgical residency is five years. They may also be trained in internal medicine (a three-year residency), followed by specialized residency training in oncology or endocrinology (hormone and metabolic diseases), which usually takes another three years.

In addition to postgraduate clinical training, residents and fellows may elect to participate in endocrine research. Research grants are available from organizations such as the American Association of Endocrine Surgery and the American Thyroid Association to support research in the areas of diagnosis, prevention, and treatment of endocrine disease, as well as in the underlying molecular, cellular, and physiologic disease mechanisms.

These residency and fellowship programs are accredited by the Accreditation Council for Graduate Medical Education. In addition, physicians are usually certified by an American Board of Medical Specialties (ABMS) Member Board, and they continually receive accredited education to update their knowledge and skills and maintain their certification.

There are relatively few endocrine specialists, compared with specialists in other fields. For example, a study conducted by the American Association of Endocrine Surgeons discovered that a small number of high-volume endocrine surgeons perform 24 percent of all endocrine surgeries. The number of specialized endocrine surgeons is projected to increase in the coming years, based on the growing number of endocrine cases and the increasing number of endocrine fellowships.

Services and procedures performed: The major endocrine tumors treated are those of the thyroid, parathyroid, and adrenal glands. Thyroid cancers usually grow from nodules within the thyroid. Less than 1 percent of thyroid nodules are cancerous.

The oncology team, led by an endocrinologist/oncologist/surgeon, is involved in biopsying, staging, and treating endocrine tumors. Thyroid tumors are usually diagnosed by needle biopsy of a thyroid nodule (this can be guided by ultrasound) or by biopsy of the excised nodule. The biopsy sample is examined under the microscope and, based on its cellular appearance, classified as papillary, follicular, medullary, anaplastic, or a mixed type. The next step is staging, based on the characteristics of the primary tumor and the degree of metastasis. The primary tumor is examined for size and extent of invasion of surrounding tissues. The presence, number, and location of metastases in the lymph nodes and in other organs are determined.

Tumors may be well differentiated or poorly differentiated, similar to tumors affecting other organs. In general, thyroid tumors that are poorly differentiated are associated with a worse prognosis. However, this is not always the case, because a patient’s prognosis also depends on other factors, such as age and health status. Anaplastic tumors, making up 1 to 2 percent of thyroid tumors, are the most aggressive type of thyroid tumor. They are poorly differentiated and are almost always fatal within twelve months of a diagnosis.

Some thyroid tumors can be treated by surgical removal of the affected parts of the thyroid; this procedure is called a hemithyroidectomy and is mainly used for low-risk papillary thyroid tumors that are localized in one lobe of the thyroid gland (the degree of risk is calculated based on several factors known to affect prognosis). Sometimes almost the whole thyroid is removed (near-total thyroidectomy) to decrease the risk of cancer spread to the recurrent laryngeal nerve or parathyroid glands. If the primary tumor is more than 1 centimeter in diameter or if metastases are present, the entire thyroid needs to be removed (total thyroidectomy). Surgeons have started to use minimally invasive endoscopic thyroidectomy techniques with smaller neck incisions for patients with low-risk, well-differentiated tumors. Although these techniques are gaining popularity, some controversy persists about the selection of patient candidates for this treatment.

Surgical removal of the tumor is often followed by treatment with radioactive iodine. Most thyroid cancer cells retain their ability to absorb iodine; radioactive iodine is taken up by any remaining cancer cells, specifically destroying them. Other cells in the body lack the ability to absorb iodine and remain unharmed. After radioactive iodine treatment, patients are given thyroid hormone pills to replenish thyroid hormone levels.

For the diagnosis of adrenal tumors, computed tomography (CT) and magnetic resonance imaging (MRI) techniques are frequently employed. Some adrenal tumors require angiography (study of the tumor blood supply) to determine if the tumor is affecting the blood supply to surrounding organs. Pheochromocytomas are rare tumors (annual incidence in the United States is 800) arising from cells in the adrenal medulla. These tumors secrete catecholamines that can cause hypertension, and raised levels of free catecholamines in the urine form the basis of the diagnostic test for pheochromocytoma. The typical treatment is surgical resection of tumors. Unresectable, recurrent, or metastatic pheochromocytoma has a five-year survival rate of less than 50 percent.

Parathyroid tumors occur in the parathyroid glands, which produce parathyroid hormones. These tumors are most commonly adenomas and rarely carcinomas. Surgery is the typical treatment. Endocrine pancreatic tumors occur in the endocrine pancreas, which constitutes less than 5 percent of the pancreas and consists of pancreatic islet cells that produce hormones such as insulin, glucagon, and somatostatin. Surgical resection is the standard treatment for endocrine pancreatic tumors.

Related specialties and subspecialties: The team that cares for endocrine oncology patients typically consists of the endocrinologist/oncologist/surgeon, radiologists, and oncology nurses.

Radiologists specialize in techniques that are used to image tumors, including X ray, computed tomography (CT), ultrasound, and magnetic resonance imaging (MRI). The radiologists work closely with the other members of the team, using various techniques to diagnose tumors in endocrine organs. Once a tumor is found, radiologists help design and execute treatment plans, including high-precision external-beam radiation therapy for pituitary tumors and postsurgical treatment of thyroid and parathyroid tumors with radioactive iodine.

Oncology nurses are involved in administering therapies to the patient, monitoring their progress, and managing any adverse effects the patient may experience while on therapy. Oncology nurses also help manage patients’ expectations of treatment efficacy and adverse effects, starting at treatment initiation, to ensure a high level of adherence to the therapy. Oncology nurses are typically registered nurses (RNs) who have undergone additional training, such as acquiring a master’s degree in nursing, and have attained certification in oncology. These certifications include oncology certified nurse (OCN), certified pediatric oncology nurse (CPON), advanced oncology certified clinical nurse (AOCN), advanced oncology certified clinical nurse specialist (AOCNS), and advanced oncology certified nurse practitioner (AOCNP) credentials. Oncology nurses maintain their certifications by periodically participating in continuing nursing education in their specialized field. Nurses are certified through nurses associations in the state where they work; these associations are accredited by the American Nurses Credentialing Center arm of the American Nurses Association.

Bibliography

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