Thyroid and parathyroid tumours
The thyroid gland is responsible for production of thyroid hormone, which plays a key role in the body’s metabolic functioning, as well as the cardiac and neurological systems. There are four major types of thyroid cancer – papillary, follicular, medullary and anaplastic. Each of them has a different clinical course and treatment protocols. Parathyroids are the small glands located near the thyroid gland responsible for maintaining the body’s calcium levels –
Are all thyroid and parathyroid nodules cancerous?
No. Many thyroid nodules are benign (non-cancerous), with no risk of spread. However they may still need surgery for removal, especially if they are increasing in size, creating trouble with swallowing or painful. They also may need to be removed if it is unclear if they are cancerous or not. They could also be safely observed in some situations. Parathyroid nodules may require surgery even if they are not cancerous because they may cause high calcium levels.
How common is it?
Thyroid cancer is relatively uncommon, with around 15,000 new cases occurring in India each year. Women have a higher risk of developing thyroid cancer than men. Cancers in the parathyroid gland are very rare.
What are the symptoms?
The symptoms of thyroid cancer are a swelling in front of the neck, difficulty or pain while swallowing, breathing discomfort or difficulty, change or hoarseness of voice and a lump in the side of the neck. The symptoms of parathyroid cancer are similar except for symptoms associated with high calcium levels – bony pains, abdominal pain, altered mental status and kidney stones.
What causes it?
Most cancers do not have an identifiable cause are associated with random genetic mutations. Some of the established causes of thyroid cancer are previous radiotherapy to the neck, long-standing iodine deficiency and goitre (thyroid swelling). Familial causes of thyroid cancer are rare, accounting for 5-15% of all cases. However they are important as they may be associated with other tumours (parathyroid, adrenal gland, colorectal and endometrium), and the patient needs screening for these as well. Families in whom multiple members have had thyroid cancer need to be screened for specific genetic mutations and when high-risk mutations are identified, children may need to undergo pre-emptive removal of the thyroid gland in childhood to prevent early and aggressive thyroid cancers from developing.
How do you diagnose it?
Evaluation of these cancers involves two parts. The first is fine needle aspiration, which is a biopsy performed with a fine needle, where cells from are studied to determine the type of cancer. The second part is imaging of the cancer with ultrasound of the neck to assess the extent to which spread has occurred. In cases where it is suspected that the tumour has invaded surrounding structures like the voice box or food pipe, CT or MRI scans may be needed. Unfortunately needle tests are not 100% accurate, meaning that the diagnosis may change after the tumour is removed and sent for pathological testing. Based on the needle test and the imaging, the best possible treatment for your cancer is determined.
How do you treat it?
Surgery is most often the best initial treatment for thyroid cancer. The goals of surgery are complete removal of the thyroid gland and the involved lymph nodes in the neck. The intricacy of the operation lies in avoiding injury to the recurrent laryngeal nerve (which controls the quality and intensity of the voice) and parathyroid glands (which control the calcium levels in the blood). Advanced thyroid cancers can involve surrounding structures like the voice box, windpipe, food pipe and major blood vessels; when the tumour can be completely resected along with a part or whole of these structures, surgery should be offered, as it is the best chance of cure. However considerable expertise is required for these surgeries to be performed successfully. In differentiated thyroid cancers (papillary and follicular), surgery is often followed by radioiodine therapy, a radioactive isotope of iodine, which kills residual microscopic thyroid cancer cells that are in the body and cannot be seen or removed surgically. When the thyroid cancer cannot be removed completely, radiotherapy is offered following surgery, while in anaplastic thyroid cancers, surgery is followed by radiotherapy and chemotherapy. In patients in whom there is spread to distant organs (lung, liver, bones), radiotherapy and/or chemotherapy are also options to improve pain and prolong survival.
Parathyroid cancers are typically treated with surgical removal of the parathyroid gland with or without the adjacent thyroid tissue and lymph nodes in the neck. Advanced tumours require radiotherapy after surgery.
Is it curable?
Differentiated thyroid cancers (papillary and follicular) in younger patients (<55 years) are associated with nearly 100% survival at 5 years. Other thyroid cancers are also curable, with the rates depend on the exact type of tumour, the stage at diagnosis and the treatment administered. Anaplastic thyroid cancer is one of the most aggressive human cancers, with only 20% of patients alive at 1 year. However each patient is different; it does not mean that patients with advanced disease do not survive. To maximize chances of survival, early diagnosis and appropriate and complete treatment from qualified specialists are of vital importance.
What does the road to recovery look like?
Surgery for an early tumour may take two weeks to recover from while a major surgery following by radiotherapy and chemotherapy may take months to completely recover from. It is important to think of your treatment as a marathon rather than a sprint, and take help from those around you, whether they are medical professionals, or friends and family. The team involved in your rehabilitation may include the speech and swallowing therapist, the physical therapist and the pain specialists. Follow-up after treatment is crucial – this is to not only assess your recovery, but also to check for recurrence. Although the vast majority of patients survive, up to third have recurrences that require further treatment. Additionally, removal of the thyroid gland requires lifelong supplementation with thyroid hormone and titration of these doses. You may also need calcium supplementation for a certain period of time. If you require radioiodine therapy, contraception is vital; this can result in birth defects in the developing fetus and conception needs to be delayed for at least a year after completion of radioiodine treatment.