Thyroid Carcinoma

Contents

Thyroid nodules are relatively common, and seen in about 5% of the population
Only about 5% of thyroid nodules are thyroid cancers
Most thyroid cancers are papillary tumours (about 80%) which are relatively benign. Their incidence appears to be increasing
Follicular tumours make up about 10-20% of cases of thyroid cancer. They are often localised only, but have the potential to spread to bone and lungs. Usually a good prognosis if detected early.
Recommended management for all follicular and papillary tumours >1cm diameter is total thyroidectomy and radio iodine ablation
Most patients will subsequently require life-long thyroxine. Doses should be titrated to completely suppress TSH levels
The remaining 10-20% of tumours are rare types, including medullary, and anapaestic tumours. These have the worst prognosis

There are five main types of thyroid carcinoma, and their properties are summarised below:

Cell type	Frequency	Behaviour	Spread	Prognosis
Papillary	70-80%	Occurs in young people	Local – sometimes bone / lung secondaries	Good, especially in young patients
Follicular	10-20%	More common in females	Lung / Bone	Good if resectable
Anaplastic	<5%	Aggressive, often constricts the airway	Locally invasive	Very Poor
Lymphoma	2%	Variable	Locally invasive	Poor – but sometimes responds to radiotherapy
Medullary cell	5%	Often familial	Local and mets	Poor, but often very slow course

Thyroid tumours are not very common – they are responsible for about 400 deaths in the UK per year.
90% of cases present with thyroid nodules.

The primary treatment is near-total thyroidectomy. Where there is local spread, more dissection of the neck may be needed.
After this initial surgery, if there is still the possibility of some diseased tissue still present, then radioiodine may be given. This is also useful as it can be used to locate metastasis.
Local lymph nodes, as well as the lungs and bones are the most common sites of spread.
After treatment, even if there is functioning thyroid tissue left, patients may be given thyroid hormone to suppress TSH secretion. This helps to monitor the presence of any further carcinoma as high levels of T3/T4 present in the blood at this stage hint at further disease presence.
The prognosis is extremely good – particularly if the patient is under 40, and the tumour confined to the thyroid –Anaplastic / lymphoma
In contrast to above, these have an extremely poor prognosis. They do not respond to radioiodine, and external radiotherapy may produce a very brief respite. –Medually carcinoma
This is often associated with multiple endocrine neoplasia.
It is usually treated by total thyroidectomy
Progression is often slow, but the tumour responds very poorly to treatment and often spreads.
The patient’s family should be screened for this and other neoplastic conditions