What is parathyroid cancer
The parathyroid glands are four small glands located on the back of the thyroid gland, responsible for regulating the body’s calcium levels. This is different from the thyroid, which produces the hormones thyroxine (T4) and triiodothyronine (T3).
Tumors in the parathyroid glands are rare and mostly benign (such as adenomas). Parathyroid carcinomas, or cancers, are very rare. The suspicion of parathyroid cancer usually arises because tumors cause hypercalcemia (an increase in the amount of calcium in the blood), leading the patient to feel tired, weak, and sleepy.
The increase in calcium occurs because the diseased cell produces an excess of a hormone called PTH (hyperparathyroidism), which removes calcium from the bone into the blood.
Symptoms and signs of parathyroid cancer
In addition to the symptoms described above, other symptoms may be found:
- Pain, especially in the bones;
- Kidney problems, including kidney stones;
- Loss of appetite;
- Intense thirst;
- Fatigue;
- Frequent urination;
- Muscle weakness;
- Lump in the neck.
Diagnosis of parathyroid cancer
Patient symptoms, blood calcium levels, and parathyroid hormone levels are factors considered during the diagnostic investigation. Parathyroid cancer can be difficult to detect because the cells of benign tumors resemble those of the disease.
After blood tests are performed and hyperparathyroidism is diagnosed, imaging tests may be requested to determine which of the parathyroid glands is overactive.
The following tests and procedures may be used:
- Imaging tests – ultrasound, computed tomography (CT) scan, or magnetic resonance imaging (MRI) help define the size and exact location of the tumor;
- Scintigraphy – may show if a parathyroid gland is overactive. The procedure involves injecting a radioactive substance into the blood through a vein in the arm, which accumulates in the overactive tissue (the cancer itself). It can also help find lesions in other parts of the body (metastases);
- Biopsy – after evidence of a parathyroid tumor, a biopsy may be performed. In the procedure, small pieces of tissue are removed and sent to a pathologist, who will confirm or rule out the cancer diagnosis. These samples can be taken through a needle and examined under a microscope for cancer cells.
Treatment for parathyroid cancer
Treatment options for parathyroid cancer depend on the results of the exams, the staging of the cancer, the possibility of controlling blood calcium levels, and whether the patient is physically able to undergo surgery.
If possible, the main treatment is indeed surgery, which aims to remove the entire tumor. Before surgery, the patient may need to take medications to control the amount of calcium in the blood until the procedure is performed.
In some cases, it may be necessary to undergo radiation therapy (a procedure that kills cancer cells through radiation) or chemotherapy (a treatment that uses medications orally or intravenously to stop the growth of cancer cells, either by killing them or preventing them from dividing).
Prevention of parathyroid cancer
There is no consensus on the risk factors specifically related to the development of parathyroid adenomas or cancer; anyone can have such a tumor. However, the risk is higher when the person:
- Has undergone radiation therapy to the neck;
- Has been exposed to high doses of radiation from nuclear plants;
- Has a family history of parathyroid tumors;
- Has certain hereditary diseases, such as familial isolated hyperparathyroidism or multiple endocrine neoplasia, types 1 or 2.
