Thyroid cancer is a type of cancer that begins in the thyroid gland (an endocrine gland formed by two connected lobes, found at the front of the neck, below the laryngeal prominence).
The thyroid gland secretes thyroid hormones, which influence the metabolic rate, protein synthesis, the appetite, the gut motility, the absorption of substances and are importantly involved in the body development. Any functional disorder of this gland can lead to severe general problems in the body and for this reason it is very accurately controlled. The thyroid gland has two main types of cells: the follicular cells and the C cells. The main role of the first mentioned is to produce the thyroid hormones that will control the metabolism meanwhile the C Cells function is the synthesis of calcitonin in order to control the levels of calcium in the body.
Thyroid Cancers typically start in follicular cells, but it can also originate in C cells.
Types of Thyroid Cancer
Doctors divide Thyroid Cancer into three major types based on the origin of the cells involved. These are:
- Differentiated (including papillary, follicular and Hürthle cell). There are 3 types of Differentiated:
- Papillary cancer: about 8 out of 10 thyroid cancers are papillary cancers. Papillary cancers tend to grow very slowly.
- Follicular cancer: also called follicular carcinoma or follicular adenocarcinoma, is the next most common type.
- Hürthle cell cancer: it is difficult to obtain a treat.
- Medullary: it develops from the C cells of the thyroid gland. This type of thyroid cancer is more difficult to find and treat. There are 2 types of MTC (Medullary Thyroid Cancer):
- Sporadic MTC: it is not inherited.
- Familial MTC: it is inherited and 20% to 25% can occur in each generation of a family. These cancers often develop during childhood or early adulthood and can spread early.
- Anaplastic (an aggressive undifferentiated tumour): this cancer is called undifferentiated because the cancer cells do not look very much like normal thyroid cells under the microscope.
The risk to get a Thyroid cancer can be boosted by factors from different nature. Some of them can be managed, for instance, by avoiding radiation, but there are others that cannot be controlled, such as hereditary conditions.
Risk factors for Thyroid Cancer include:
- Female sex
- Hereditary conditions
- Diet low in iodine
Signs and Symptoms
Despite the fact that some cancers cannot be detected until they are in an advanced stage of development, it may be important to keep in mind some of the symptoms that can warn us about its presence:
- A lump that can be felt through the skin on your neck
- Changes to your voice, including increasing hoarseness
- Difficulty when swallowing
- Pain in your neck and throat
- Swollen lymph nodes in your neck
Survival in Thyroid cancer is strongly linked with tumour stage; and also depends on the nature of the cells involved. In the three main types of thyroid cancer explained before, the survival rate at 5 years in early stages (I and II) is 100% approximately. Nevertheless, in more advanced stages there are some differences between the different types of cancer, being the survival rates more or less about 80% in the 3rd stage. It has been noticed ―in stage IV― that in capillary and follicular thyroid cancer is the 5-years survival rate is 50%, meanwhile in medullary thyroid cancer is very much lower. Being a rare condition but not less important, the anaplastic-like cancer is very lethal since most patients diagnosed with this kind of cancer live between 2 and 6 months.
Thyroid Cancer Diagnosis
PLEASE NOTE: EARLY DIAGNOSIS IN CANCER IS VERY IMPORTANT BECAUSE CANCER THAT’S DIAGNOSED AT AN EARLY STAGE ―BEFORE IT’S HAD THE CHANCE TO GET TOO BIG OR SPREAD― IS MORE LIKELY TO BE TREATED SUCCESSFULLY. IF THE CANCER HAS SPREAD, TREATMENT BECOMES MORE DIFFICULT, AND GENERALLY A PERSON’S CHANCES OF SURVIVING ARE MUCH LOWER.
State of the Art
Generally, different techniques have been employed in order to diagnose the presence of thyroid cancer. The most used are imaging techniques, biopsies, blood tests and physical exams. Nevertheless, some limitations are found because of the stress on the patient derived from the extraction of a piece of tissue, the low efficacy from the blood test prediction, the low resolution of the physical explorations or the high cost of some methods such as the computerized tomography scans, the positron emission tomography or the ultrasound system.