What are the clinical features of Thyroid Cancer?

Thyroid cancer can occur in all age groups, but is more common over the age of thirty. It is three times more likely to occur in women and most patients present with a nodule in their thyroid. The clinical features vary depending on the time of presentation. An early presentation may be just a neck lump with no symptoms. A late presentation may have additional features of hoarseness (due to pressure on the recurrent laryngeal nerve) or difficulty in swallowing and eating. It is important to realise that thyroid nodules are common, and it has been estimated that about 10% of the population will have them. Less than 5% of all thyroid nodules are malignant.

What is the prognosis of Thyroid Cancer?

The overall prognosis of thyroid cancer is better than most other cancers. The most common types of thyroid cancer (Papillary and Follicular) have the best prognosis. The cure rates of these cancers in the young are as high as 95%.

Age at the original therapy is a critial predictor of patient outcome. Patients under 40 years old have a good prognosis and low recurrence rates. By the age of 60 years these rates are much worse.Children tend not to be diagnosed early and present with positve lymph nodes in the majority of cases. Despite this the prognosis of papillary cancer is exellent in adolescence.There is an exception, children diagnosed less than 10 years old can do badly. Gender effects risk. Men are at greater risk than women of extrathyroidal invasion and locoregional lynph node involvement. Delay in treatment greater that 12 months is associated with a 2 times increase in mortality at 30 years. This has implications in patients with false negative fine needle aspirations of the thyroid where correct treatment is known to be on average delayed by 28 months. The extent of surgery has a profound effect on prognosis in moderate to high risk patients. Total thyroidectomy reduces mortality and recurrence rate. This is not true for low risk cases where more conservative treatment does not go hand in hand with poor results. Radioactive iodine is known to reduce recurrence and mortality in high risk tumours but there is little evidence of this effect in low risk tumours. Thyroid hormone suppression therapy has an important role in management. TSH suppression is associated with a reduction in recurrences. This effect is only seen in stage 111 and 1V disease when the TSH was suppressed to less than 0.1mIU/L.A similar effect is seen with stage 11 disease with a TSH suppressed to between 0.1 to 0.5 mIU/L. The prognosis of stage 1 disease is so good that TSH suppression has no added bebeficial effect.!

Medullary cancer is rarer than papillary and follicular cancers, but has a worse prognosis. It is more aggressive and tends to spread to lymph nodes at an early stage.

Anaplastic thyroid cancer has the worse prognosis of all the thyroid cancers as it often presents after it has spread. Rarely can an operation remove the entire tumour.