Parathyroid cancer is extremely rare with less than 400 cases reported globally in 2008. It mostly occurs in people in their mid-forties (about ten years earlier than primary hyperparathyroidism occurs on average) and it can affect both men and women.
Causes
Radiotherapy treatment to the neck and head can cause non-cancerous (benign) parathyroid growths called adenoma. This may also increase the risk of developing a cancerous parathyroid tumour.
People with genetic conditions such as multiple endocrine neoplasia 1 (MEN1) or familial hyperparathyroidism have a higher risk of parathyroid cancer. These are rare conditions caused by a gene change (mutation) passed on from parent to child (inherited).
You can find out more information about these conditions from Amend, a patient organisation supporting MEN patients.
Symptoms
Parathyroid cancer is usually associated with higher calcium and PTH levels than in primary hyperparathyroidism and is likely to cause more severe symptoms.
Severe symptoms of hypercalcaemia are: muscle weakness, fatigue, depression, nausea, polydipsia and polyuria, bone pain, and fractures. Recurrent severe pancreatitis, peptic ulcer disease, and anaemia can also occur.
Other problems may occur in your kidneys or bones.
You may be able to feel a lump in your neck.
Diagnosis
Almost all people with parathyroid cancer have over active parathyroid glands which produce too much parathyroid hormone (PTH) and cause high serum calcium levels, but this is not always the case. Rarely, some tumours are non- functional and may be misdiagnosed as thyroid cancer.
Parathyroid cancer can be difficult to diagnose before surgery and is sometimes only recognized months or years later when the disease recurs.
You may at first be diagnosed with Primary Hyperparathyroidism as symptoms and blood test results appear similar. Advances in genetics are making it easier to distinguish between benign and malignant disease.
Very high calcium and PTH levels, kidney and bone involvement, neck lump and recurrent laryngeal nerve palsy indicate the need for further investigation.
You will be referred to an endocrinologist for treatment at hospital where further blood tests and scans will be carried out.
Often, a diagnosis can only be given after surgery by means of a pathology test.
If positive, you will have further scans to the whole body to see if the cancer has spread.
- CT (computerised tomography) scan
- MRI (magnetic resonance imaging) scan
- PET (positron emission tomography) scan
You will be told if the cancer is within the parathyroid glands or nearby tissue (localised) or if it has spread elsewhere in your body (metastatic).This is called staging.
Treatment
Treatment for parathyroid cancer is surgery. Early recognition and complete removal of the affected gland gives the best outcome. You may be offered radiotherapy after surgery.
Surgery
The operation is called a parathyroidectomy and it should be carried out by a highly skilled surgeon. As well as the affected parathyroid gland(s), the surgeon may also need to remove other affected tissue.
Low concentrations of PTH after surgery can cause a condition called hypoparathyroidism which may be temporary or permanent. If you experience ‘pins and needles’ or cramps it is very important that you seek advice from your doctor as soon as possible.
Temporary hypoparathyroidism : This can cause symptoms of low calcium (hypocalcaemia) such as ‘pins and needles’ or cramps which is not uncommon and will usually settle down in a few weeks. These symptoms are a sign of your body adjusting to new PTH levels and usually pass, though you may need calcium supplements and over- the- counter vitamin D3 during this phase.
Permanent hypoparathyroidism: If low PTH does not recover due to damage of the glands or if you have had most of your parathyroid glands removed this condition will be permanent. Let your doctor know immediately of any symptoms as soon as possible as your calcium may drop after surgery. You will be given treatment with vitamin D analogues, Vitamin D3, magnesium and calcium supplements. This is a rare, lifelong condition but you will not be alone. Hypopara UK has been supporting hypopara patients since 2005 – please visit our section on Hypoparathyroidism for more information and to join our support group.
Medical treatment
If you are unable to have an operation for any reason you will be offered drug treatment to reduce the PTH and calcium levels. This works well but can only treat the symptoms not the disease itself.
You may be prescribed:
Cinacalcet (Mimpara). This reduces the release of PTH and so lowers the concentration of calcium. This helps to reduce symptoms and improve quality of life. It does not seem to improve bone density or reduce the risk of developing kidney stones. Some patients may develop side effects, most commonly, nausea.
Follow-up
You will receive long term care from your endocrinologist and oncologist with regular check ups and blood tests.
If you have any problems between appointments, let your Endocrine Nurse know as soon as possible.
Support
It takes time to come to terms with having a rare cancer, let alone manage the challenge of hypercalcaemia or the rare condition of post surgical hypoparathyroidism as well. Let your feelings flow as they arise.
Talk to people who understand.
You can find more information and support for cancer at Macmillan. Talk to your Macmillan nurses.
For managing high or low PTH and calcium levels, you can call our helpline on 01342 316315 or join our support groups.
References
Parathyroid Carcinoma: Marcocci, Cetani, Silverberg,Pinchera, Bilezekain. J Bone Miner Res 2008 Dec; 23(12): 1869–1880. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3276344/
Macmillan https://www.macmillan.org.uk/information-and-support/parathyroid-gland-tumours#293316