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thyroid cancer

25
May
2017
0

Thyroid cancer: How human race has almost won the fight against a difficult enemy

Dr. Shawn T. Joseph, Associate Consultant, Head & Neck Surgical Oncology

“It is not just curable with this surgery, but even your quality of life will be unhampered and you will live as long as you would have, if you had not developed this disease”. As I was concluding my counseling to Eliz, the 25 year old emerging architect, who had come to me with a recent diagnosis of thyroid cancer, I saw rays of hope back in her wet eyes. She was recently married and was part of a growing firm of four young and ambitious architects. Correcting her voice which sounded broken during most parts of our discussion, she thanked me and agreed for the surgery. Now, two years later, she is disease free, has progressed in her career and life, with a will much stronger than before. As I reminisce her case and of others treated for thyroid cancer with similar outcomes, I can only thank the consistent effort put in by generations of medical scientists who have worked to bring about excellent outcomes in thyroid cancer treatment, for any disease of thyroid requiring surgery was considered doomed not long before. Present day patients of thyroid cancer and doctors who treat them owe a lot to those doctors who have fought an unrelenting battle against a disease which seemed impossible to even alleviate, if not cure, and faced severe criticisms and ridicule, during the time they practiced.

Thyroid gland removal or thyroidectomy is one of the safest and effective surgeries at present, for diseases of thyroid which require surgery. Even cancers of thyroid can be cured in about 90% of patients by way of surgery and adjuvant therapy. It would be hard to believe that thyroidectomy was one of the most condemned surgeries till the latter part of 19th surgery, due to extremely high procedure related mortality and morbidity rates. Cancers which have spread to distant parts of the body are usually treated with a palliative intent only as most of these are considered incurable. But in case of thyroid cancer, it is possible to treat and control disease which has spread to distant parts of the body with radio iodine therapy, which is a major leap and milestone in the treatment of any cancer. This change from 75% of patients dying due to any form of thyroid surgery even for a non cancer disease to reaching a >90% cure rate with cancer of thyroid with zero procedure related death and extremely low morbidity represents the fight generations of medical scientists have put forward in tackling this problem, once considered impossible to treat.

As the fear of increasing incidence of cancer looms large over the human race, it is probably worth remembering the war human race has fought against thyroid cancer and how they, from a position of no hope, have almost conquered it.

What is Thyroid gland and why it is important

Thyroid, the small butterfly shaped gland situated in front of our neck is essential for most of our bodily functions. But it also represents a marvelous fight human beings have put against the most perilous disease of our times- ‘cancer’.

It may be hard to imagine that this small gland which weighs just about 25 grams has control over almost all major functions of the body by way of its control over metabolism and protein synthesis. This starts right when you are in your mother’s womb, for a deficiency of thyroxin- the hormone it produces can severely hamper intellectual development. Thyroid hormones- thyroxin and calcitonin play an important role, right from normal brain development of a fetus to maintaining the rhythm of heart beats of an adult.

It derives its name from the Greek ‘Thyroideus’, which means ‘shield like’, probably due to its shape. But by way of its function in shielding the body against numerous problems, thyroid gland justifies the meaning of that name. It plays important role in controlling basal metabolic rate of the body, cardiac rhythm, ensuring normal development, maintaining normal sexual function, sleep, thought patterns etc.

Increasing thyroid cancer- is it real or an increase in detection alone?

The world observes September as the ‘Thyroid Cancer Month’.

There is an appreciable increase in the incidence of thyroid cancer in most regions of the world in the past few decades. The number of thyroid cancer patients has shown an increase in India as well, with some states like Kerala showing a threefold increase in number over the past three decades. There is an ongoing debate among physicians whether this is a real increase or an apparent increase in number due to increasing imaging investigations. Though this is not clear, it is generally considered to be an increase in detection of thyroid cancer by way of increase in imaging investigations for management of diseases of thyroid or unrelated to it. However, it is striking that mortality from thyroid cancer has seen a steady decline over the years. It is at present one of those cancers with the highest cure rates.

Treatment of thyroid cancer requires a multi modality approach, with surgery being the main stay. Other treatment modalities like radioactive iodine, hormonal suppression and rarely external beam radiotherapy or chemotherapy may also be required as adjuvant.

History of thyroid surgery

The story behind the therapeutic triumph against thyroid cancer dates back to ancient times and is marked by heroic efforts at surgery of thyroid and collaboration of scientists belonging to different fields.

At present times, the 5 year survival of differentiated thyroid cancer, which forms 90% of all thyroid cancers, is close to 95%. Complications which can arise from thyroid surgery are an injury to the recurrent laryngeal nerve, which is the voice nerve, which is very rare these days in expert hands and mortality from surgery is almost unheard of. And today there are debates concerning ambulatory thyroid surgery and endoscopic thyroid surgery. Contrast this with 1850s, when many major centres around the world had a mortality rate from thyroid surgery, be it benign or malignant, of around 75%, which brought about a ban for thyroid surgery, by the Academy of Medicine in France. It is said that the eight patients among the first twenty thyroid surgeries that Theodore Billroth, a legendary surgeon of 19th century performed had died due to the surgery itself. And in a well known quote John Dieffenbach, a surgeon from Berlin, had stated in 1848 that, “thyroidectomy was one of the most thankless, most perilous undertakings, which if not altogether prohibited, should atleast be restricted”. Thyroid surgery was dismissed as foolhardy performances by most European surgeons of that time.

The scenario of thyroid surgery changed dramatically in the latter half of 19th century, thanks mainly to a Swiss surgeon by name, Emil Theodore Kocher, the first surgeon ever to win a Nobel prize, who worked to promote antiseptic wound treatment and minimizing blood loss in thyroid surgery. This was a time when the advent of Anesthesia and antiseptic techniques had made a huge impact in the surgical outcomes. The mortality from thyroid surgery, as reported by Kocher in his patients, came down to 0.5% by 1900. This was due to the meticulous surgical techniques of Kocher, his understanding of finer anatomy of thyroid and the strict peri operative care given to the patients.

The success with effective thyroid surgery made surgeons realize another problem, that of their patients developing problems associated with thyroid gland deficiency. This led researchers to work on this, leading to isolation of thyroxin, the thyroid hormone, by Edward Calvin Kendall of Mayo Clinic on the Christmas day of 1914. This later led to synthesis of thyroid hormone by the London Chemical Pathology Professor, Sir Charles Harington in the 1920s, slowly solving the problems associated with thyroid hormone deficiency arising out of surgical removal of thyroid gland.

Alongside these surgical advances, was the discovery of X- ray by Roentgen in 1895 and its use to produce tissue damage. Emil Grubbe of Chicago was one of the first physicians to use x rays in the treatment of cancer. With studies and reports from multiple centres across the world, soon radiation therapy became an important part of cancer treatment. It could be used as primary treatment of solid tumors or to treat microscopic disease left after surgery. Many refinements in radiation equipments and delivery have made it more effective over the years. But it had its side effects and limitation of dose and the area where it is given. It was not possible to treat cancer which has spread to distant parts with either surgery or radiation.

Radio iodine and why it represents a major leap in any cancer treatment

Thyroid gland concentrates most of the iodine in the body, iodine being the essential ingredient for thyroid hormone production. The American physician Saul Hertz discovered the use of Radio active iodine for the treatment of thyroid diseases in 1941. His studies in collaboration with the physicist Arthur Roberts of Massachusettes Institute of Technology demonstrated tracer capabilities of radio active iodine and its effects on thyroid gland. This made an important addition to the surgical treatment of thyroid cancer, as it is practically impossible to predict 100% removal of thyroid gland by surgery. There is always the possibility of leaving microscopic thyroid tissue near critical structures like the recurrent laryngeal nerve and parathyroid gland which maintains calcium metabolism of the body, in an attempt to preserve its function. The discovery of radioactive iodine made it possible to target even microscopic remnants of thyroid tissue, left after surgery, without significantly affecting any other organ in the body, as almost 80% of the iodine is absorbed by thyroid tissue alone. Also radio iodine made it possible to treat thyroid cancer which has spread to distant parts of the body. This was a paradigm shift in the treatment of cancer, as cancers which have spread to distant parts of the body are usually considered extremely difficult to treat. Now, from a time when thyroid surgery for even a non cancer was considered impossible, we were reaching a position where we can treat even disseminated thyroid cancer, that too without major morbidity. The role of external beam radiation in thyroid cancer has significantly come down after the emergence of radioactive iodine therapy.

Now we have emerging drugs which can act on molecular level targets involved in the causation of recurrent and advanced thyroid cancer. It may not be long before we can cure differentiated thyroid cancer of any stage with molecular targeted therapy.

Thyroid cancer treatment in many ways reflects the fight human beings have put against the most vicious disease of our times, cancer. From a period when there was a ban on thyroid surgery for even benign tumors, due to the almost certain mortality, we have reached an age where we are curing more than 90% of thyroid cancers, without any significant morbidity. A triumph which is marked in the history of modern medicine as the combined effort of medical scientists belonging to multiple specialties, different generations, and different geography, all united by the passion to make their contribution in the preservation of the ever enigmatic mystery called Life.

MAIN TYPES Papillary thyroid cancer
Follicular thyroid cancer
Medullary thyroid cancer
Anaplastic thyroid cancer
SYMPTOMS Firm to hard swelling in front of neck*
Unusual firm recent onset swelling on the sides of neck
Unusual Voice change
Difficulty in swallowing food
Difficulty in breathing
Kindly note that as most of these symptoms can occur in other conditions as well, consult your family physician first in case of doubt
INVESTIGATIONS Thyroid function tests*
Ultra sound scan of neck
Fine needle aspiration cytology from the swelling
Calcitonin, calcium, Carcino. Embryonic antigen (medullary carcinoma)
Genetic tests (rarely
* Please note that a normal thyroid function test alone does not mean presence or absence of thyroid cancer
TREATMENT OPTIONS

(Varies from case to case)

Surgery
Radioactive iodine
External beam radiation
FOLLOW UP Blood tests like Thyroglobulin, anti thyroglobulin antibody, thyroid function tests
Ultra sound scan of neck
Calcitonin, CEA (in case of medullary thyroid cancer)
PROGNOSIS Excellent
More than 90%cases of thyroid cancer can be cured if appropriate treatment taken