How does thyroid cancer progress?

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Thyroid cancer affects nearly 570,000 people worldwide every year according to the World Health Organization (WHO), 75% of whom are women. In the US, about 12,000 men and 35,000 women get thyroid cancer every year according to the Centers for Disease Control and Prevention (CDC). Thyroid cancer is characterized by the appearance of cancerous cells in the thyroid gland, forming a malignant tumor. If left untreated, these cells can migrate to other organs. This phenomenon is called metastasis. In this article, we review the different types of thyroid cancer, its prognosis, the various stages of the disease and existing treatments.

What are the different types of thyroid cancer?

Thyroid cancers are of four main types:
  • Papillary cancers are the most common, accounting for 80 to 90% of cases. These are differentiated thyroid cancers with cancerous cells retaining some of the characteristics of healthy cells.
  • Follicular cancers, also called vesicular cancers, account for 10% of cases. They are also differentiated cancers. They tend to be slightly more aggressive than papillary cancers.
  • Medullary cancers are rare cancers that develop from thyroid cells called C cells. They are very often familial or hereditary cancers.
  • Poorly differentiated and anaplastic thyroid cancers are even rarer. They mainly affect elderly people and progress very rapidly.

Is it a serious disease?

The prognosis for thyroid cancer is very good. The cure rate exceeds 90% and recurrences are rather rare. The prognosis essentially depends on:
  • The age of the patient: the disease is more serious in patients over 45 years of age.
  • The type of cancer: differentiated thyroid cancers (papillary and follicular cancers) are much less serious than undifferentiated cancers.
  • The stage of the disease: the more or less advanced development at the time of diagnosis also influences the chances of cure. 

What are the stages of thyroid cancer?

To evaluate the stage of thyroid cancer, physicians use the TNM classification system of the Union for International Cancer Control (UICC). They examine:
  • The primary Tumor: attributing a score between 0 and 4 depending on its size and its extension to the thyroid tissue.
  • Nodes: with a score between 0 and 3 depending on their number, size and extension.
  • Metastasis: with a score of 0 or 1 depending on the absence or presence of metastasis.
This grid is used to determine the stage of the thyroid cancer, that is the extent of the spread:
  • At stage 1, there is a single, small tumor
  • At stage 2, the tumor is bigger, in a single area
  • At stage 3, the cancer has extended to nearby lymph nodes
  • At stage 4, the spread is wider with metastasis in other organs.

What are the treatments for thyroid cancer?

Surgical Treatment

Surgery is the first step in the treatment of thyroid cancer. A total thyroidectomy or removal of the thyroid gland is recommended for all malignant tumors larger than 1 centimeter in diameter. The surgical procedure aims to eliminate all thyroid tissue to minimize the risk of tumor recurrence and facilitate further treatment.
The surgery is performed under general anesthesia. As with any surgery, removing the thyroid gland carries risks, such as involuntary damage to the parathyroid glands. These glands release a hormone that helps control the level of calcium in the body and damage to these glands can lead to disruptions in their function. Innovative technologies such as FLUOBEAM® LX help surgeons identify and preserve the parathyroid glands during thyroid removal, thanks to the natural autofluorescence of these glands. As such, the use of FLUOBEAM® LX reduces the risk of accidental injury.
Learn more about thyroid surgery risks 

Other Treatment

Following surgery, medication is prescribed. Synthetic thyroid hormones, identical to thyroxine (T4), must be taken to offset the absence of thyroid. Regular monitoring of TSH (thyroid-stimulating hormone) levels is also required. It confirms the correct hormonal balance.
The use of iodine-131 may be considered in certain cases, in particular when there is a risk of recurrence. Treatment with radioactive iodine allows targeted destruction of thyroid tissue that may persist after surgery and which may contain tumorous cancer cells.

Key Figures 

  • 570,000 people worldwide diagnosed with thyroid cancer every year 
  • 75% of women
  • Cure rate over 90%

Thyroid cancers are therefore cancers with high cure rates. The prognosis depends on several factors, such as the patient’s age, the type of cancer and the stage of the disease. Early diagnosis increases the chances of cure. Treatment is mainly surgical, with thyroid removal performed under general anesthesia. After the operation, hormone replacement therapy must be taken for life.


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