indiacancer.org - Thyroid Cancers

Thyroid Cancers

		What is the thyroid gland?
		What is cancer of the thyroid?
		How does cancer of the thyroid present?
		How is thyroid cancer detected?
		What are the types of thyroid cancer?
		What are staging and grading?
		How are thyroid cancers treated?
		What are the side effects of treatment for thyroid cancer?
		What is the importance of follow up?

What is the thyroid gland?

The thyroid is an important gland located in the midline in the front of the neck. It is a shield shaped gland, with a right and left lobe on each side of the midline, and it is placed over the Adam's apple, which is the prominent cartilage of the voice box or the larynx.

The function of the thyroid is to secrete iodine dependent hormones which help the body to function normally.

Thyroid

	What is cancer of the thyroid?

Thyroid

A cancer seen in an age group spanning 25 to 65 years, it is more commonly seen in women than in men. It is also seen to develop 20 to 30 years after a child has been exposed to radiation in large doses, either for treatment or accidentally.

	How does cancer of the thyroid present?

	Cancer of the thyroid usually presents in the form of a painless swelling at the base of the neck in the midline, which initially moves up and down with swallowing, but later may become fixed. The early signs are quite similar to common cold or flu, or other common diseases. If the person develops one of the following symptoms which refuses to go away such as:
		Pain in the front of the neck.
		Difficulty in breathing, speaking or swallowing may occur later on as the disease becomes advanced and invades the wind pipe, the voice box and the food pipe respectively.
		There could also be excessive activity, increased hunger and eating but with loss of weight if the tumor is producing too much hormones.
		The reverse symptoms could also occur if the tumor is producing too little hormones.

	How is thyroid cancer detected?

	If cancer of the thyroid is suspected, the doctor will perform the following investigations:
		An ultrasound of the neck, to locate the swelling, the number of swellings and whether the swelling is cystic (fluid filled) or solid.
		A fine needle aspiration cytology (FNAC) to get some cells from the tumor to be examined under the microscope, in order to establish a diagnosis and to find out which type of cancer.
		A series of blood tests and special scans to find out if the tumor is producing too much hormone.

What are the types of thyroid cancer?

	There are 4 main types of cancer of the thyroid (based on how the cells look under the microscope):
		Papillary.
		Follicular.
		Medullary.
		Anaplastic.
	Medullary thyroid cancer may be passed from generation to generation in some families, because of a defective gene in the family. These inherited medullary thyroid cancers may also be associated with other tumors of the suprarenal glands (pheochromocytoma) and hyperparathyroidism (over functioning parathyroid glands). This complex of diseases is known as MEN 2 (Multiple Endocrine Neoplasia type 2), in which again there are subtypes. These relatives of medullary thyroid cancer patients thus need to be thoroughly screened, and if the defective gene is located, even if at that moment in time they do not have cancer, they should undergo removal of the thyroid gland.

What are staging and grading?

These are terms with which you must become familiar, if you are dealing with any form of cancer.

When we stage a cancer, we try to establish carefully degree of spread of the cancer and if indeed there is spread, to what extent and involving which organs.

The grading of a cancer is a microscopic issue, in which the pathologist lets you know how aggressive this particular type of cancer is; well differentiated means less aggressive, moderately differentiated intermediately aggressive and poorly differentiated more aggressive.

Both grading and staging help your clinician to establish the prognosis or how serious your disease is and what is going to be the likely outcome.

Staging may require additional imaging tests such as CT Scan, MRI, Sonography of the abdomen, Bone scan or chest X-ray.

Papillary and Follicular carcinomas of the thyroid

Stage I
Cancer in one or both lobes of the thyroid, but not beyond the thyroid.

Stage II
If the patient is less than 45 years of age, cancer which has spread beyond the thyroid
If the patient is greater than 45 years of age, cancer restricted to the thyroid but greater then 1 cm in diameter.

Stage III
Cancer in patients greater than 45 years of age and has spread to outside the thyroid, but not beyond the neck or has spread to the adjacent lymph nodes. (Lymph nodes are small bean-shaped structures, which act as stations for drainage of lymph, a clear watery fluid, which courses through out the body in transparent, thin tubes called lymph channels or lymphatics,from various organs.)

Stage IV
Cancer in patients of age greater than 45 years which has spread beyond the neck.

Medullary carcinoma of the thyroid

Stage I
Cancer less than 1 cm in size.

Stage II
Cancer between 1 and 4 cms in size.

Stage III
Cancer has spread to the lymph nodes in the neck.

Stage IV
Cancer has spread to distant parts of the body

Anaplastic carcinoma of the thyroid

There is no staging. This is a very aggressive cancer, which grows and spreads faster than other varieties of thyroid cancer.

How are thyroid cancers treated?

A lot depends on the patient's constitution, the grade of her disease and its staging. Patients are usually treated by a team of specialists which utilizes a multipronged approach. This includes an an oncosurgeon, a nuclear medicine specialist, and a radiotherapist. The plan of treatment is tailored to fit a patient's requirements. If necessary, chemotherapy may become an add on.

Treatment strategies.

Surgery is the bastion of treatment for cancer of the thyroid.
Lobectomy removes only one lobe of the thyroid.
Hemithyroidectomy removes one lobe plus the isthmus, which is a belt like band of thyroid tissue crossing the midline and joining the 2 lobes of the thyroid.
Near total thyroidectomy removes almost all of the thyroid
Total thyroidectomy removes the entire thyroid gland. This last is still the most preferred procedure amongst most oncosurgeons.

An additionallymph node dissection in the neck may be carried out, especially in the case of papillary or medullary thyroid cancers.

Radioactive iodine is a special therapy which is given to patients of thyroid cancer for surgery is found to be inadequate. The iodine binds to the cancer cells and its radioactive effect destroys them. It is of no use in medullary carcinomas of the thyroid.

The alternative local therapy to surgery is radiation therapy. This involves the use of high energy, penetrative rays to destroy cancer cells. It affects cancer cells only in the zone treated. Radiation therapy is also employed for palliation i.e. control of symptoms alone in an advanced cancer.

Radiation therapy can also be used in adjunct to surgery or chemotherapy, either before or after.

Teletherapy or external radiation is given via a machine remote from the body while brachytherapy or internal radiation is given by implanting a radioactive source within the involved tissues. Patients may or may not require both modalities of radiation.

Radiotherapy, after initial planning, usually takes just 5 to 10 minutes per day, 5 days a week for about 6 weeks. This time period is flexible depending upon the modality of radiation used.

Besides local therapy and radio iodine, the best attempt to control cancer cells circulating in the body and lodged at places other than the thyroid is by using systemic therapy (therapy which affects the entire systems of the body) which is in the form of injections or oral drugs. This form of treatment is called chemotherapy.

This form of treatment is given in a cyclical manner (each set of drugs is repeated usually after every 3-4 weeks).

Chemotherapy can also be used in combination with surgery, radiotherapy or both, either before or after.

Hormone therapy may also be used if the tumor is believed to be hormone sensitive.

What are the side effects of treatment for thyroid cancer?

	Surgery for thyroid cancer should be undertaken only in institutes which are experienced in this kind of surgery. The surgery can be very morbid in the wrong hands and it is one of the technically more difficult surgeries to perform. Often the result of surgery may not be favorable if done by inexperienced hands. A patient undergoing total thyroidectomy will have to go on a life long replacement therapy for thyroid hormones, and even perhaps calcium, as the parathyroid glands may also have to be removed, which are just next to the thyroid. Unfortunately treatment for cancer does cause damage to the healthy tissues. Please ask the clinician about any possible side effects before any form of treatment commences. The effects of radiation depend upon the dose of radiation, the size of the area radiated, and the number and size of each fraction. The commonest side effect is extreme fatigue. Although bed rest is good, most radiotherapists ad1ise the patient to be as mobile as possible. Another common problem is that of radiation dermatitis in which the skin covering the radiated area becomes red, dry, itchy, and may show signs of scaling off. This will slowly settle down after radiation ceases, but there may be a permanent 'bronzing' of the skin. It is important to note here that this skin problem is associated only with teletherapy or external radiation therapy. Radiation also may cause nausea and vomiting, diarrhea, urinary discomfort. There may also be a fall in the white blood cells, which are needed by humans to fight infection. Usually the radiotherapist can suggest the drugs and diet necessary to alleviate such problems.The various drugs in chemotherapy cause a varied spectrum of side effects. The severity and variability of these symptoms are very individualistic, changing from patient to patient. Some of the common side effects are:
		Skin rashes.
		Loss of hair.
		Diarrhea.
		Vomiting.
		Tingling and numbness in the fingers and toes.
		Hearing loss.
	Most are temporary and recede after therapy is over. Hair growth gradually starts after cessation of chemotherapy. The medical oncologist will usually be able to reduce the severity and spectrum of these side effects. The psychology of the patient is very important during therapy. Better psychologically prepared the patient is, better are his chances of having decreased side effects. The patient should drink large quantities of water while the therapy is in progress, and preferably avoid uncooked or raw food. Water should be filtered or boiled. Any relative or person who has any sort of infection such as common cold should be asked to desist from coming close to the patient.

What is the importance of follow up?

The importance of follow-up cannot be overemphasized. It is a fatal fallacy to assume on the patient's part that once the primary or the first phase of treatment is over, then he or she is cured. It must be stressed here that cancer has a notorious proclivity of coming back again and again. The only way to fight this is to pick up any problem when it is still early, so that it can be nipped in the bud. And the only way to do this is to follow up when the doctor calls you for the next visit. Each such visit will include a detailed history, a physical examination (including an internal i.e. a rectal or vaginal examination), a chest x-ray, an ultrasonography or a CT scan, and various other blood studies as indicated.