What is thyroid cancer?
Even though thyroid cancer is not frequently discussed, it is nevertheless important to be informed about it, considering the significant increase in new cancer cases in the last 20 years, especially among women. In addition to the well-known hyper- and hypothyroid issues that are linked to a malfunction of the thyroid gland, there exists another recurrent pathology also tied to the thyroid gland, caused by the appearance of nodules in the thyroid; those are small masses embedded in the parenchyma of the thyroid, which are found in morethan half of all women over 50 years of age. It is believed that this increased diagnosis in the last couple of years is directly linked to the technical advancements in medical imaging in the last two decades. The technology allows for the slightest tissue anomaly within the thyroid to be detected swiftly and accurately. Although the majority of thyroid nodules are benign and will never become cancerous, some nodules could evolve to malignant ones or could even be the first signs of an existing thyroid cancer.
When faced with a suspicious thyroid lump, the first thing a doctor will ask for is an ultrasound to check for any thyroid nodules. In the presence of a nodule, another medical exam called scintigraphy, is required to determine the nature of the nodule. Scintigraphy is a medical imaging technique that consists of injecting a specific radioactive blood tracer, which allows for doctors to check the functional status of the nodule. An increased uptake means the nodule is “hot”, or hyperactive. A decreased uptake means it is “cold” or a hypoactive nodule. This distinction is an important one as cold nodules have a higher propensity to become (or already be) cancerous in the long run. Then, the doctor will either opt for closely monitoring the nodule or request a fine needle aspiration biopsy to check for any cancerous cells.
There exist many types of thyroid cancers, with the majority of them belonging to well-differentiated tumors that can be divided into two groups: papillary and follicular types. On rare occasions, some thyroid cancers belong to medullary cancers and undifferentiated tumors such as anaplastic cancers.
The vast majority of papillary and follicular tumors are relatively slow to evolve and are frequently non-aggressive. These tumors can easily be treated by surgery followed by a specific treatment with high dose radioactive iodine. For these types of thyroid cancers, patient survival depends on the stage of the disease but is generally good, with a survival rate above 95% after 5 years. With medullary or anaplastic cancers, however, tumors are more aggressive and have a tendency to spread quickly to the rest of the body. The survival rate for these tumors is in general lower than that of well-differentiated cancers.