Anaplastic Thyroid Cancer

RESUMO DE ABERTURA
  • Anaplastic thyroid cancer (ATC) is an aggressive form of thyroid malignancy that can sometimes be resistant to drug therapy. It spreads quickly from the thyroid to other regions of the body and can impair the normal pattern of reflex conduction in the nerves and muscles.
  • The prognosis of ATC is worsened by late diagnosis and ineffective therapy. The survival rate is pegged at six months, and at least one death is recorded in every five confirmed diagnoses after one year.
  • The main cause of ATC is still unclear; however, there is an increased risk of ATC in patients with preexisting case thyroid carcinoma. The link between ATC and the gene pool of diagnosed patients is currently the focus of much medical research.
  • Compared to other thyroid dysfunctions, ATC significantly impairs reflex conduction. This form the basis for a confirmatory diagnosis: the gold standard for ATC diagnosis is the Fine Needle Aspiration (FNA) technique.
  • The thyroid blood test cannot be used to measure the rate of reflex impairment. This test can only determine the level of TSH and other Thyroid hormones in the blood. The findings of Dr Richard Bayliss has shown that TSH is not a good indicator of thyroid functioning. The Thyroflex test is considered a more accurate method of diagnosis and follow-up approach for therapy assessment. This test directly evaluates Thyroid functioning by measuring the rate of reflex conduction in the body.
  • Therapy plan for ATC is focused principally at reducing the rate of malignant cell proliferation. Currently, the recommended plan is integrative in nature and include a strictly supervised combination of surgical resection, external beam radiotherapy, chemotherapy, and bioidentical hormones in cases of thyroid hormone imbalance.

INTRODUÇÃO: Apresentação clínica e visão geral da doença

Tissue malignancies are considered serious disease states in human biology regardless of the body region affected. Thyroid malignancies are however peculiar in their occurrence and extended effects on the body reflexes and biological system coordination. In essence, Thyroid cancers have been estimated to represent about 1% of all human cancer cases, with a rising incidence in the developing counties and industrialized nations of the World. Though rare in occurrence, Thyroid cancers can be debilitating, presenting with a poor prognosis when not diagnosed early or properly managed.

Anaplastic Thyroid Cancer is an undifferentiated type of thyroid malignancy, generally occurring in people with a strong link of iodine deficiency and a prior history of thyroid dysfunction (Papillary or Follicular Thyroid Cancer).

It accounts for less than 2% of all Thyroid cancer diagnosis and presents in most cases as an aggressive malignancy with resistance to most conventional treatment modalities for thyroid dysfunction. Medical stats on survival rate for ATC are discouraging, with a reported average survival rate of 6 months translating to the death of 1 in every five diagnosis case after 12 months.

The pathophysiology of Anaplastic Thyroid Cancer has generated intense debate within the medical community. In large part, the primary cause of ATC is unclear. Judging from recent research results, ATC is hypothesized to result from a terminal differentiation of preexisting thyroid carcinoma, which was untreated, or in most cases undetected. Genetic enquiries have established a genetic predisposition, with a common link between the onset of ATC development and the gene construct of susceptible individuals in the population. Affected patients are usually adults within the age range of 20 – 90 years.

As excepted of an aggressive cancer form, ATC has a rapid progression, spreading in a lateral pattern to bones of the lower body, lungs, and the brain. ATC cells, although undifferentiated, pathologically present as giant, squamous, spindle-shaped, and highly vascular masses. The roles of thyroid antibodies in Anaplastic Thyroid cancers are yet unknown with no substantial evidence or literature document suggesting their production during the course of this disease. However, most patients with ATS present with a normal level of T4 and T3. Calcitonin levels are reported to be significantly raised in some forms of Thyroid cancer.

Patients are suffering from Anaplastic Thyroid Cancer present with a neck mass causing difficulty in swallowing and upsetting the normal breathing pattern. With a high mitotic index, the cancer mass divides rapidly within the neck region and invades structures within. In most cases, the mass partially blocks the vocal cords and cause noticeable hoarseness in the voice of the patient. Some patients have also presented with enlarged lymph nodes. The range of symptoms noticed in patients are not definite and depends on disease course and precipitating factors.

Abordagem de diagnóstico atual e método de tratamento

The prognosis of Thyroid cancers generally depends on early diagnosis, symptom management and treatment plan. Molecular Biomarkers titration, biopsy and imaging methods are the primary methods of a thyroid cancer diagnosis. The gold standard for the diagnosis of ATC is the Fine Needle Aspiration (FNA) technique with a confirmatory test balanced on a thyroid blood test and sometimes, medical imaging tests. The FNA test differentiates ATC from other forms of Thyroid malignancies. In some cases, the rapidly dividing mass outgrows its blood supply and become necrotic, making a definite diagnosis by a single FNA test very difficult. A large needle core biopsy is performed to confirm the diagnosis of ATC and exclude other forms of Thyroid dysfunction initially suspected.

Conventional treatment of ATC with symptoms management requires a periodic Thyroid blood test. However, the use of Thyroid blood tests in the management of Thyroid dysfunctions, including thyroid cancer forms, for tracking the levels of thyroid hormones is currently obsolete and phased out in practice. According to the findings of Dr R.I.S Bayliss, thyroid hormones are most concentrated in the skin, muscle and brain at a 75% estimate, with the blood holding a meagre 18% of these hormones. Resultantly, Thyroid blood test results are not a true representation of the actual thyroid hormone level.

Compared to the end artifacts of Thyroid function, which Thyroid blood tests aim to quantify, the Thyroflex directly assesses the reflex and symptom presentation of the patient as a more accurate determinant of thyroid function. Accuracy of Reflex testing in determining Thyroid function as been pegged at about 75% from different clinical trials. The useful role of Thyroflex in The management of ATC for Symptom management and thyroid function determinant is becoming more recognized across the globe.

Treatment Protocol for Anaplastic Thyroid Cancer

Therapy plan for ATC is multimodal –involving different simultaneous treatment approach focused principally at reducing the rate of malignant cell proliferation. Currently, the recommended plan is integrative in nature and include a strictly supervised combination of surgical resection, external beam radiotherapy, chemotherapy, and bioidentical hormones in cases of thyroid hormone imbalance.

Single-agent chemotherapy is not a recommended treatment choice in ATC patients. In cases where drug treatment is preferred, multidrug therapy involving the simultaneous use of drugs such as Cisplatin, Doxorubicin, and Docetaxel is the acceptable standard. With the level of aggressiveness of ATC, chemotherapy is solely useful in cases of early diagnosis and rare slow disease progression.

Extensive metastasis of ATC in patients who were not diagnosed early is the main indication for surgical resection. Thyroidectomy has proven extremely useful in ATC cases where cell division is localized within the thyroid parenchyma. External Beam Radiation therapy is a novel method which has been proven by a few clinical trials to offer benefits to patients initially treated by surgical resection. This approach has, however, been widely criticized in recent times due to its potential to induce acute toxicity.

The use of Bioidentical hormones in ATC management is considered a second line supplementary therapy. Currently, these hormones are targeted at balancing normal thyroid hormone levels as choice therapy progresses.

The highly differentiated phenotype and aggressive nature of ATC have called for a patient-oriented supervised management therapy, with a continuous real-time update of symptom severity and disease remission or otherwise.

REFERÊNCIAS