May 5, 2016 - Thyroid Cancer

Question 1

Incidence of Thyroid Cancer

Answer 1

Has greatly increased in recent years.

Likely due to better detection due to the widespread availability and low-cost of the ultrasound machine.

Question 2

Types of Thyroid Cancers

Answer 2

Differentiated Thyroid Cancers make up 95% of all thyroid cancers of which the most common is papillary (80%) and follicular (15%).

Undifferentiated thyroid cancers include medullary (<5%), anaplastic (1%), and lymphoma (1%).

Question 3

Risk of Growth / Metastases (Papillary vs. Follicular)

Answer 3

Medullary is VERY unlikely to grow or metastasize if the nodule is less than 2cm in size.

Follicular is much more likely to grow or metastasize if the nodule is less than 2cm in size. This has a poorer prognosis.

Question 4

Prognosis of Thyroid Cancer

Answer 4

VERY good.

If caught early, the 20-year survival rate is 99%.

Even if caught late, there is still a very good 20-year survival rate of ~60%.

Question 5

Most Common Metastases Sites

Answer 5

Lung and bone

Question 6

Treatment of Thyroid Cancer

Answer 6

1. Surgery
2. Consider radioactive iodine therapy
3. Thyroid hormone suppressive therapy

Question 7

Thyroglobulin

Answer 7

The structure on thyroid cells in which iodine is used to make thyroid hormone. This is used as a cancer biomarker.

After surgery and radioactive iodine, the thyroglobulin levels should be undetectable. If these start to creep up later in life, it might mean that the cancer is coming back.

Question 8

Medullary Thyroid Cancer

Answer 8

Derived from C-cells (parafollicular cells)

Calcitonin is produced and used as a biomarker.

20% is familial cancer in this case.

Question 9

Surveillance after Treatment

Answer 9

Patients need lifelong surveillance.

Neck ultrasounds for the first 5 years.

Yearly bloodwork to monitor biomarkers.