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Thyroid Cancer


OVERVIEW OF Thyroid Cancer :

When the cells grows out of the control within the thyroid gland it leads to the formation of  thyroid cancer.


STRUCTURE of Thyroid Cancer :

The Thyroid gland secreate thyroid hormones which monitores the metabolic reactions. It is an endocrine gland meaning it secreates its hormone via bloodstream. The thyroid gland consists of two lobes which are connected by the Isthmus. It is rich in blood vessels and the nerves responsible for the quality of voice are also present here.


CAUSES :

Enlarged thyroid glands due to Iodine deficiency (goitre)

Genetics

Obesity

Thyroiditis

Exposure to Radiation therapy and harmful radiation


PATHOPHYSIOLOGY :

Pathophysiology of thyroid gland:

There are 4 types of thyroid cancer namely Papillary carcinoma, Follicular carcinoma, Medullary carcinoma and Anaplastic  carcinoma.

Papillary carcinoma of thyroid:

It occurs due to the exposure to radiation in children. It consists of colloidal filled follicles with papillary projections. In some lesions calcified structures are found within them which are called as Psammoma bodies. These are the diagnostic feature of papillary carcinoma when it is viewed under the microscope. It spread by lymphatic. It shows excellent prognosis.

Follicular carcinoma of thyroid:

It occurs usually in combination with the multinodular goitre or endemic goitre.  They are very rapidly growing. It can be present as a solitary nodule. If the goitre is hard and it shows restricted mobility then follicular carcinoma can be considered. Metastasis is higher incase of follicular carcinoma of thyroid. It spread by blood.

Anaplastic carcinoma:

Majority of the patient with Anaplastic carcinoma shows rapidly growing tumour with shorter duration.  The surface is irregular and it is hard in consistency. Early infiltration into the trachea results in Stridor. It shows worst prognosis.

Medullary carcinoma of thyroid:

It is familial.These cells are derived from the parafollicular cells of the thyroid gland. The hormones produced by the medullary carcinoma of thyroid include Calcitonin, Prostaglandin, Serotonin and Adrenocorticotrophic hormone. It gets spread by both lymphatic and blood.

 


COMMON CLINICAL SIGNS AND SYMPTOMS :

  • A lump in the neck, sometimes growing quickly
  • Swelling in the neck
  • Pain in the front of the neck, sometimes going up to the ears
  • Hoarseness or other voice changes that do not go away
  • Trouble swallowing
  • Trouble breathing
  • A constant cough that is not due to a cold


DIAGNOSTIC :

Biopsy:

It is the removal of a small amount of tissue for examination under the microscope. A biopsy is the confirmatory test for stomach cancer.

Fine needle aspiration:

In this type of biopsy the physician moves the fine needle  through the abdomen and take the tissue needed for the diagnosis.

Endoscopic biopsy:

In this type of biopsy, the physician uses an endoscope an hollow tube . light emitting structure to down the stomach and tissues are obtained.

Blood test:

Patient with the stomach cancer  tends to show low levels of platelets, white blood cells, red blood cells.  This results in the aneamia in patients. Complete blood count might reveal whether the bleeding is occurring or not.

Computed tomography:

A CT scan takes three dimensional pictures of the abnormal tissues from different angles.

Magnetic Resonance Imaging:

A MRI scan uses the combination of the magnetic and radiowave frequency to view the abnormal tissues.

An dye is injected in the vein or the patient is asked to swallow the dye and the results are observed.

Ultrasound:

A sound waves to create the picture of the internal organs to find out if the cancer is spread or not.

Abdominal ultrasound:  with the patient symptoms it can be used to view the pancreas. But it cannot reveal the spread of pancreas.

Endoscopic ultrasound: in this method the doctor uses an ultrasound probe, and with the guidance of endoscope it is passed in to the small intestine and then into the pancreas to view the structures.

Barium Swallow:

The patient is asked to swallow the liquid Barium. Barium gets deposited in the lining of the stomach ,

esophagus and small intestine.

If X rays are taken at this time it might show some blockages in the stomach and other areas clearly.

This test is done for advanced level of thyroid cancer

Positron emission tomography (PET) or PET-CT scan:

A PET scan is a way to create pictures of organs and tissues inside the body. A small amount of a radioactive sugar substance is injected into the patient’s body. This sugar substance is taken up by cells that use the most energy. Because cancer tends to use energy actively, it absorbs more of the radioactive substance. However, the amount of radiation in the substance is too low to be harmful. A scanner then detects this substance to produce images of the inside of the body.

 


TREATMENT AND PROGNOSIS :

Surgery:

  • Total/Near total Thyroidectomy

In this the total thyroid gland is removed. In some cases parathyroid and recurrent laryngeal nerve are preserved which is known as Near total thyroidectomy.

  • Chemotherapy:

 

  • A chemotherapy is after the sugery or before the surgery to shrink the cancer cells. A chemotherapy is nothing but the delivery of drug intravenously

 

  • Radiation therapy:

It uses powerful x rays or emission of protons to destroy the cells. The radiation therapy also aids  in shrinkage of the cells and also relief the symptoms caused by the cancer.

  • Radioactive iodine therapy:

 

   It is done by taking radioactive iodine orally. The cells relating to the thyroid cancer and thyroid glands are removed.

 

  • Immunotherapy
    • it is a drug treatment that uses your immune system to fight cancer. Your body's disease-fighting immune system may not attack your cancer because the cancer cells produce proteins that blind the immune system cells from recognizing the cancer cells. This immunotherapy boos those cells and helps the body to fight against it.
  • Targeted therapy:

This therapy involves targeting the specific organs. It involves the emission of rays.

  • Hormonal replacement therapy:

 The T3,T4 synthetically prepared thyroid hormones are given as the part of the treatment. This treatment is very effective and it helps in monitoring the TSH activity.


PROGNOSIS :

Mostly 8 out of 10 people tends to have papillary carcinoma of thyroid. Papillary  carcinoma of thyroid is curable and shows good prognosis.

  • Follicular: Close to 100% for localized; around 63% for metastasized.
  • Papillary: Close to 100% for  localized;around 80% for metastasized.
  • Medullary: Close to 100% for localized; around 40% for metastasized.
  • Anaplastic: Close to 31% for localized; 4% for metastasized.

 


PREVENTION :

Don’t neglect the initial symptoms

Reduces the exposure to the radiation

Take healthy diet

Avoid alcohol consumption

Follow the healthy diet

Be physicaly active

 


Medicines used in the Treatment :

Medicines used in thyroid cancer:

  • Dacarbazine
  • Vincristine
  • Cyclophosphamide
  • Doxorubicin
  • Streptozocin
  • Fluorouracil
  • Paclitaxel
  • Docetaxel
  • Carboplatin


REFERENCE :

https://www.cancer.org/cancer/thyroid-cancer/detection-diagnosis-staging/signs-symptoms.html

https://www.cancer.gov/types/thyroid

https://my.clevelandclinic.org/health/diseases/12210-thyroid-cancer

https://www.endocrineweb.com/conditions/thyroid-cancer/thyroid-cancer

https://www.cancer.org/cancer/thyroid-cancer/about/what-is-thyroid-cancer.html