Thyroid Cancer
Thyroid
The Thyroid gland is about 2 inch long, butterfly shaped organ located on the front side of the throat. It is one of the largest endocrine glands.
Also know more about : Throat Cancer
Functions
The Thyroid gland synthesizes two vital hormones: triiodothyronine and thyroxine which are responsible for regulating body’s temperature, heartbeat, metabolism, growth, appetite, menstrual cycle etc.
Thyroid Cancer
Thyroid Cancer is a type of tumor located within the thyroid gland which may be in the benign or malignant state. Four types of Thyroid Cancer could be differentiated till date – Papillary, Follicular, Medullary and Anaplastic Thyroid Cancer.
Types of Thyroid Cancer
- Papillary Cancer: It accounts for 80% of the thyroid cancer occurrences. It grows slowly and spreads gradually over different parts. It can often be treated successfully and are rarely fatal.
- Follicular Cancer: This cancer is mostly caused due to lack of Iodine in the diet.It accounts for 10% of the total thyroid cancer occurrences. They usually do not spread to the lymph nodes but they can spread to other parts of the body. The prognosis of follicular cancer is good but the rates are lower than papillary cancer.
- Medullary Cancer: It accounts for 4% of thyroid cancers. This type of thyroid cancer is more difficult to find and treat. It can be further classified as:
- Sporadic Medullary Thyroid Cancer:It accounts for about 8 out of 10 cases of Medullary Thyroid Cancer. It occurs mostly in older adults.
- Familial Medullary Thyroid Cancer : It is an inherited condition accounting 20% to 25% occurances in each generation of a family. These cancers often develop during childhood or early adulthood and spreads rapidly.
- Anaplastic Thyroid Cancer: This is a rare form of thyroid cancer, amounting up to 2% of all thyroid cancers. This cancer is referred as undifferentiated. It often spreads quickly into the neck and to other parts of the body, and is difficult to treat.
Occurrences of Thyroid Cancer
A recent study on the topic, revealed that Thyroid Cancer is the most common type of endocrine- cancer amounting 3.8% of all cancer cases. Here is a depiction of the global occurrence of Thyroid Cancer.
| Type | Occurrence Rate |
| Papillary Cancer | 80% |
| Follicular Cancer | 15% |
| Medullary Cancer | 3% |
| Anaplastic cancer | 2% |
Thyroid Cancer is a common cancer type and its diagnosis tends to scare the patients, however most cases of Thyroid Cancers are highly treatable and can be cured with surgery and other advanced treatments.
Anatomy of thyroid gland
Anatomy of Thyroid Cancer
The symptoms of thyroid cancer vary from person to person. Some people may not experience any symptom till the later stages until the physician diagnose the lump in the neck during routine health examination while some may experience prominent early symptoms. The most common symptoms of thyroid cancer are as
- Lump in the neck
- Hoarse voice
- Pain in the neck or behind the ears
- Swollen lymph nodes in the neck.
- Difficulty in swallowing
- Sore throat
- Difficulty in breathing
- Cough that lasts longer than 3 weeks
There are various causes which contribute towards the increased risk of developing Thyroid Cancer. Some of them are given below:
- Exposure to radiation for a prolonged period probably during the childhood.
- Individuals with certain health conditions like Cowden’s syndrome, a rare autosomal disorder can easily fall a prey to Thyroid Cancer.
- Abnormality or mutations in certain genes can result in the development of Thyroid Cancer.
- Thyroid Cancers like other types of Cancers can develop in individuals who have a family history of Cancer.
- Inadequate amount of iodine in the diet can also result in the development of Thyroid Cancer.
Most cases of Thyroid Cancer cannot be prevented. However in some cases, certain preventive measures can reduce the risk of developing Thyroid Cancer to a great extent. Some of those measures are outlined below:
By avoiding exposure to radiation:
The cells of the Thyroid gland (and most other glands) are very sensitive to x-rays and other forms of radiation, and easily destroyed or mutated if exposed to it. If you are advised a CT scan by your healthcare professional for any underlying illness , consult with your physician for any other alternative measures like MRI etc since the amount of radiation emitted by CT SCAN is 50 times greater than that of the radiation emitted by MRI or X- rays.
Radiation exposure especially in children increases the risk of Thyroid Cancer. Imaging tests such as x-rays and CT scans also expose children to radiation, but at much lower doses. The exact measure of exposure that might raise the risk of Thyroid Cancer is yet not clear.
Avoid residing near a nuclear power plant:
The surroundings or neighbouring areas should be thoroughly scrutinized while selecting the place of residence. It is advised to select a place that is located at least 10 miles away from the resident area.
If an individual is residing in a place which is near to any nuclear power plant then extreme preventive measures should be taken in case of nuclear fallout. A suitable dosage of potassium iodide needs to be administered to those individuals who are residing in places of nuclear emergency.
Maintaining proper level of Iodine:
The Thyroid gland needs a steady supply of iodine to function properly and to synthesize its hormones.
Iodine deficiency causes the Thyroid gland to swell initially causing goiter, but chronic deficiency promotes nodules and highly increases the risk of Cancer. Iodine can be consumed through common salt or through fish / shellfish.
Blood tests for gene mutations:
If an individual have familial history of Thyroid Cancer, then it is highly recommended to opt for a blood test. A gene mutation can predominantly cause familial medullary Thyroid Cancer (MTC).
Regular Thyroid Screenings:
Most of the Thyroid Cancer cases can be found in the early stages. Oncologists recommend self examination of the neck area at least twice a year and a medical screening once a year.
Special precautions during child bearing age:
Gender or age cannot be prevented but we can be a bit more vigilant with self exams and screenings. Women are 3x more likely than men to develop Thyroid Cancer and about 65% of cases occur during childbearing years (20-45 years).
Usually Thyroid Cancers are staged on the basis of TNM staging systems. Here are listed the number staging systems which doctor uses for Cancer staging.
T indicates the size of the main (primary) tumor and whether it has grown into nearby areas.
- TX: Primary tumor cannot be accessed.
- T0: No evidence of primary tumor.
- T1: T1 stage is the earliest possible stage of Thyroid Cancer where the tumor is entirely within the Thyroid gland and the size of the tumor does not exceed 2cm.
- T1a: The tumor is not over 1 cm and is limited to Thyroid gland.
- T1b: The tumor size ranges from 1 cm to 2 cm and is limited to the Thyroid gland.
- T2: In this stage the tumor is only inside the Thyroid gland but the size of the tumor is slightly larger than that of T1 stage. In T2 stage the tumor mass is within 4 cm.
- T3: In this stage the size is larger than 4 cm and the Cancerous growth is seen spreading across the walls of the tissues surrounding the Thyroid gland.
- T4: T4 stage ranges from moderately advanced stage to highly advanced stage.
- T4a: The tumor can be of any size and it has grown excessively beyond the Thyroid gland into the nearby glands. It is called moderately advanced stage.
- T4b: The tumor size is significantly larger and expanding the region beyond the Thyroid capsule to the surrounding vessels invading the adjacent soft tissues like pre vertebral fascia, larynx, esophagus etc. This is also called very advanced disease.
N: N denotes regional lymph nodes. Numerous lymph nodes are located in the region of head and neck. These can be further classified into N0 and N1.
- N0: There are no lymph nodes involvement or the tumor is clinically or radio logically node negative.
- N1: These denote that the Cancer has spread to the adjacent lymph nodes. It can be further referred to as clinically or radio logically node negative.
- N1a: The Cancer has spread to lymph nodes around the Thyroid in the neck.
- N1b: The Cancer has spread to other lymph nodes in the neck (called cervical) or to lymph nodes behind the throat or in the upper chest
M: Here M denotes distant metastasis which means that the Cancer has spread to the distant tissues and organs.
- MX: Distant metastasis cannot be assessed.
- M0: There is no distant metastasis.
- M1: The Cancer has spread to other parts of the body, such as distant lymph nodes, internal organs, bones, etc
It is difficult to estimate the exact survival rate of patient as the survival rates of patients suffering from Thyroid Cancer can vary from one individual to another. Here are outlined the survival analysis of 5 years study of patients who were victims of different branches of Thyroid Cancer.
Cancer stats at a glance
Papillary Thyroid Cancer
Based on patients diagnosed 1998 to 1999
| Stage | 5-Year Relative Survival Rate |
| I | near 100% |
| II | near 100% |
| III | 93% |
| IV | 51% |
Follicular Thyroid Cancer
Based on patients diagnosed 1998 to 1999
| Stage | 5-Year Relative Survival Rate |
| I | near 100% |
| II | near 100% |
| III | 71% |
| IV | 50% |
Medullary Thyroid Cancer*
| Stage | 5-Year Relative Survival Rate |
| I | near 100% |
| II | 90% |
| III | 71% |
| IV | 21% |
Based on patients diagnosed between 1985 and 1991
It comes to a relief, as most Thyroid Cancers can be detected early due to their prominent symptoms, like neck lumps or nodules. Early Thyroid Cancers are also sometimes diagnosed during ultrasound tests or blood tests. However, to be sure proper tests and diagnostics are essential also a few people may not experience the signs and symptoms at the early stages. Some of the investigation and diagnostic test which your doctor may advice to detect the TNM stages of Thyroid Cancer are as follows.
- Physical examination of the tumor: The very first step in the detection of Thyroid Cancer is the physical examination of the affected area by your healthcare professional. In this process of examination, you will be asked questions related to your current condition, previous medical history, your present symptoms etc.
- Biopsy: The FNAC biopsy is one of the most important tests to detect Cancer. This involves aspirating some of the tissues with fluid from the lymph node of the suspected tumor and observing the tissues under microscope. The whole process of biopsy is performed under local anesthesia to ease the pain and discomfort of the patient. In some insances where the FNA biopsies fail to detect the Cancerous growth than, other types of more invasive biopsies are performed. They include a ‘core’ biopsy or an open biopsy and in some rare cases, a lobectomy is performed which is the removal of the major portions of the effected Thyroid gland that is performed under general anaesthesia in operation theatre.
- Imaging Tests: One or more imaging tests are usually advised by the physician to know about the benign or metastatic nature of the tumor, or to find any suspicious areas in the neck which might denote Cancer. These imaging test include
- Ultrasound: This is an imaging test which creates images of the body parts by utilizing sound waves. This test is usually helpful in determining the physical state of the Thyroid nodule whether it is solid or a fluid filled mass.
- Radio iodine scan: This test is mainly used in papillary or follicular Thyroid Cancer to determine if the Cancer has spread to other parts of the body. This scan is usually performed by injecting some amount of radioactive iodine. The areas affected by the Cancer readily absorb the radioactive solution which can be monitored under a special camera.
- CT SCAN and MRI SCAN: Cross sectional images of the effected region can be generated by CT SCAN while detailed images of affected as well as adjacent soft tissues can be obtained from an MRI SCAN.
- Blood Test: Blood tests are usually used to monitor if the Thyroid is functioning in a normal or abnormal manner. These tests may include TSH test (Thyroid stimulating hormone test), PTH test (paraThyroid hormone test), Thyroid hormone test etc. Some other blood tests are also advised which includes routine blood test, kidney function test and liver function test.
There are several treatment options which are alone or in combination implemented to treat Thyroid Cancer depending the severity of the disease. They include
- Surgery:
There are three types of standard surgical procedures which are used to remove the tumor surgically. They include lobectomy surgical procedure which removes the Thyroid Cancer induced lobe, Thyroidectomy which involves the partial or total removal of the whole Thyroid gland. - Radiation Therapy:
Following surgery radiation therapy is implemented to prevent episodes of reoccurrence of Cancer cells. There are types of standard radiation therapy – the external as well as the internal radiation therapy. The former is the one in which a machine is used externally to kill the timorous growth while the latter implies the administration of radioactive substance internally which may be either incorporated in wires or needles. The radiation oncologist decides which therapy is required for a particular individual depending on the stage of the tumor. - Chemotherapy:
Chemotherapy is administered either before or after surgical procedure to shrink the tumor size and to prevent it from spreading to nearby organs. Chemotherapy is given either through oral or intravenous route depending upon the severity of the disease. - Hormone Therapy:
Hormonal therapy is usually given orally which stops the Cancer from growing by blocking the action of certain hormones required for the survival of tumor cells. - Targeted Therapies:
These innovative new drugs stop the growth of Cancer cells by interfering with certain proteins and receptors or blood vessels that supply the tumor with what it needs to grow. Targeted drugs treat Throat Cancer by taking advantage of specific defects in Cancer cells that fuel the cells’ growth. These drugs can be used in combination with chemotherapy or radiation therapy.
If the Cancer is detected in its early stage then proper measures can be taken to reverse it, extending the survival of the patient. However, for later stage diagnosis the treatment involves only conservative measures where palliative medicine aids in relieving the symptoms associated with it.
It is recommended that you perform TSH test at least once in six months. However if you notice any kind of symptoms associated with Thyroid Cancer, it is recommended to consult with your healthcare professional at the earliest.
Keep yourself updated with the symptoms as well the risk factors associated with this disease so that once something fishy is going on within your organs, seek medical help at the earliest.
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