A Close Look at Parathyroid Carcinoma
Author: Botheina Ghandour PhD
Overview
Parathyroid cancer or parathyroid carcinoma is a rare cancer that develops in the
parathyroid glands. These glands are located behind the thyroid gland in the front of the
neck. These glands regulate calcium levels via the parathyroid hormone (PTH).
Parathyroid carcinoma causes the gland to become overactive, and an excessive amount
of PTH is secreted, leading to hypercalcemia (Cleveland Clinic, 2023).
Secondary treatment options like chemotherapy and radiation are limited, so the
prognosis of this cancer is largely dependent upon how much of the tumor is successfully
resected. Furthermore, more than half of the patients diagnosed with parathyroid
carcinoma experience recurrence or the cancer coming back (Cleveland Clinic, 2023).
Cause/Research
The cause of parathyroid carcinoma is not properly understood; however, certain rare
genetic disorders are considered risk factors for this cancer. Those disorders are
hyperparathyroidism-jaw tumor syndrome (HPT-JT), multiple endocrine neoplasia type I
(MEN1), and familial isolated hyperparathyroidism (FIHP). Germline mutations in the
CDC73 gene (formerly known as the HRPT2 gene) cause HPT-JT, and some parathyroid
tumors also show this mutation (Shattuck et al. 2003). Hence, mutations in the CDC73
gene may increase the risk of developing parathyroid carcinoma. Furthermore, past
radiation exposure to the neck or head may increase your risk for parathyroid carcinoma
(Cleveland Clinic, 2023).
Parathyroid carcinoma is exceptionally rare, and most parathyroid tumors are benign
adenomas that mimic the symptoms of carcinomas (Stanciu et al., 2023). Research is
underfunded and overlooked due to these facts (Machado and Wilhelm, 2019). Currently,
the genetic understanding of this cancer is minimal outside of the CDC73 mutations.
Moreover, some cases show no identifiable mutation. That, coupled with the lack of
identification of environmental or lifestyle triggers, underscores the need for increased
awareness and dedicated research efforts.
Diagnosis/Treatment
Parathyroid carcinoma is challenging to diagnose, as its histological features are similar
to those of a noncancerous parathyroid adenoma. In addition, both tumors cause the
parathyroid gland to be overactive. A complete diagnosis is usually made after the
overactive part of the gland is surgically removed (parathyroidectomy) and
histopathological evidence is obtained (Cleveland Clinic, 2023). Diagnosis can be
achieved by utilizing tests like the blood calcium test and the blood PTH test as
biochemical indicators. Imaging techniques, such as a CT scan or MRI, can help
determine if the tumor has metastasized.
Surgical interventions are the primary treatment option. Surgeons may also have to
remove cancerous tissue from other parts of the body if the tumor has metastasized
(Cleveland Clinic, 2023). Treatments like chemotherapy and radiation are not commonly
used to treat parathyroid carcinomas; however, your healthcare provider can determine if
these interventions are suited to you. Lastly, medications like Cinacalcet (Sensipar) can
be used to manage the symptoms of hypercalcemia (Cleveland Clinic, 2023).
Key Takeaways
Parathyroid carcinoma is a rare cancer with treatment that is limited to surgical options.
There are no known ways to prevent or reduce the risk of developing this cancer. The
cause of parathyroid tumors is yet to be fully unfolded. There is an urgent need to further
investigate this disease. As a result, funding and patient participation in clinical trials is
urgently needed. The evolution of cancer therapies will provide more options to
supplement surgical interventions.
Sources
Cleveland Clinic. (2023). Parathyroid cancer.
https://my.clevelandclinic.org/health/diseases/6182-parathyroid-cancer
Machado, N. N., & Wilhelm, S. M. (2019). Parathyroid Cancer: A Review. Cancers,
11(11), 1676. https://doi.org/10.3390/cancers11111676
Shattuck, T. M., Välimäki, S., Obara, T., Gaz, R. D., Clark, O. H., Shoback, D., Wierman,
M. E., Tojo, K., Robbins, C. M., Carpten, J. D., Farnebo, L. O., Larsson, C., & Arnold, A.
(2003). Somatic and germ-line mutations of the HRPT2 gene in sporadic parathyroid
carcinoma. The New England journal of medicine, 349(18), 1722–1729.
https://doi.org/10.1056/NEJMoa031237
Stanciu, M., Cipaian, R. C., Ristea, R., Vasile, C. M., Popescu, M., & Popa, F. L. (2023).
Challenges in the Diagnosis of Parathyroid Cancer: Unraveling the Diagnostic Maze.
Reports, 6(3), 40. https://doi.org/10.3390/reports6030040
