Thyroid cancer

The etiology and pathogenesis is not clear. It has been established that in 80-90% of cases, cancer develops against the background of an existing goiter (diffuse hyperplasia, nodular hyperplasia, benign tumors (adenoma). This once again proves the need for morphological verification of any nodal formation in the thyroid gland.

By morphological structure, thyroid cancers are divided into differentiated and undifferentiated.

The first group includes papillary, alveolar, follicular cancers and their various combinations. Differentiated tumors (except papillary) are treatable with radioactive iodine. Long-term results are favorable in most patients.

The undifferentiated cancers are solid (medullary), squamous, round-cell tumors, their unfavorable course.

T1N0Mo- the tumor site is located in one lobe of the thyroid gland, does not extend beyond the capsule, there are no metastases to the regional lymph nodes.

T2No-1M0 – tumors that occupy the entire share of the gland, have infiltrating growth, germinating capsule and, as a rule, giving regional metastases.

T3N2MO – spreads to the entire gland, the capsule and surrounding tissues germinate, squeezes the trachea and return nerves, immobile, there are metastases in the regional and paratracheal lymph nodes.

T4N1-2M1 – a tumor of any size, but gives distant metastases. More often, a large tumor grows in the neck organs: the trachea, esophagus, neurovascular bundle, etc.

The classification of thyroid cancer in recent years has undergone many changes. The TNM classification of malignant tumors is currently adopted by the International Cancer Alliance (5th edition). In this classification, the stage of thyroid cancer depends not only on the size of the primary focus, the metastatic lesion, but also on the age of the patient and the morphological form of the tumor.

The clinical picture depends on the stage, the size of the tumor and its germination in neighboring organs (difficulty swallowing, shortness of breath, asthma attacks and excruciating shooting pains in the back of the head, chin, shoulder), with the involvement of recurrent (complete loss of voice) and sympathetic nerve (Horner symptom – retraction eyes, prolapse of upper eyelid and constriction of pupil Also common symptoms are observed: weakness, weight loss, loss of appetite. Characterized by spasmodic tumors with surrounding tissues, the restriction of its mobility, dense texture and bumpy surface. Thyroid cancer accounts for 0.4 – 2% of all malignant neoplasms of the head and neck. The incidence of this pathology in the Russian Federation (1996) was 1.1 per 100,000 people. among the male population and 3.8 per 100,000 people. among the female population.

Hormonal effects. Elevated levels of thyroid stimulating hormone in the pituitary gland (TSH) in the blood is an important etiological and pathogenetic factor in the development of thyroid tumors. Suppression of thyroid hormone secretion of TSH causes a therapeutic effect in differentiated thyroid cancer.

Ionizing radiation. Recently, more and more observations have been noted, indicating ionizing radiation, as an important cause of the development of thyroid cancer. Among the population of Japan, exposed to the explosion of atomic bombs in years. Hiroshima and Nagasaki, thyroid cancer was observed 10 times more often than among the rest of the Japanese population. The increase in the incidence of thyroid cancer in the areas affected by ionizing radiation after the accident at the Chernobyl nuclear power plant (in Russia – the Bryansk, Tula, Ryazan and Oryol regions), according to V.V. Dvirina and E.A. Axel (1993), the incidence of thyroid cancer in children 5-9 years after the accident increased 4.6 – 15.7 times compared with the national average.

Initial symptoms often escape the attention of medical professionals, which delays the examination of the patient and can lead to unreasonable conservative or inadequate surgical treatment. In this regard, patients with nodular formation of the thyroid gland more than 0.8 cm should be puncture biopsy with the aim of excluding a malignant tumor.

In specialized oncological institutions, the number of patients with thyroid cancer after non-radical primary operations began to increase, since 90.8% of patients with thyroid cancer operate in general surgical departments and only 9.2% in oncological institutions in the country. Errors of preoperative diagnosis of thyroid cancer inevitably lead to tactical errors. In particular, an analysis of the tactics of treating patients with thyroid cancer in the general surgical wards of hospitals in the Moscow region showed that non-radical operations were performed in 84.9% of cases (A.I.Paces , 1990).

Nodular formations of a thyroid gland of a neoplastic nature, as well as hyperplastic processes in the absence of an obvious positive dynamics from the ongoing conservative therapy should be removed. At the same time, given the relatively high risk of detecting thyroid cancer on this background, extracapsular surgical intervention should be performed in the volume of hemithyroidectomy with resection of the isthmus. The remaining share of the gland can fully compensate for the body’s need for thyroid hormones, and in the event of a malignant tumor in a remote macropreparation, this volume of surgical intervention can be considered radical. Preventive lymphosection is not performed and the question of surgical treatment is solved with clinically implemented metastases. The presence of metastasis of thyroid cancer in the regional areas with differentiated tumor forms (papillary and follicular adenocarcinomas) does not worsen the prognosis of the disease.

Radiotherapy of differentiated forms of thyroid cancer is not effective and does not improve long-term results of treatment of patients. Radiation therapy is indicated for patients with undifferentiated thyroid cancer and is used in combination with a surgical method for the treatment of medullary thyroid cancer.

Hormone therapy is prescribed for therapeutic, replacement purposes and prophylactically ( adjuvant ). For therapeutic purposes, it is advisable to prescribe it to patients with differentiated thyroid cancer (inoperable cases) or to treat distant metastases of papillary or follicular thyroid cancer.Hormone therapy with replacement purposes is prescribed after performing thyroidectomy or after resection of the gland in the presence of hypothyroidism. To do this, you need to know the level of thyroid hormones in the patient’s blood, the doses of drugs are selected individually, the treatment is carried out under the supervision of an endocrinologist. As a rule, hormone therapy with thyroid drugs begins on the 7-9th day after the operation and largely depends on the amount of surgical intervention. Suppressive treatment is carried out by levothyroxine at the rate of 1.8 – 2.2 µg / kg of weight (150 – 200 µg per day). The level of TSH should be maintained in the range of 0.05 – 0.1 mU / l. The initial dose of levothyroxine after hemithyroideiectomy is 50-100 mcg per day, after subtotal resection – 150-200 mcg, thyroidectomy 200-300 mcg per day. The choice of an individual dose of hormones within the specified limits depends both on the clinical picture, the patient’s body weight, the presence of concomitant cardiovascular pathology, and the effect of treatment and the dynamics of laboratory data. Contraindications for the appointment of this treatment are: acute myocardial infarction, myocarditis, untreated adrenal insufficiency. Dose adjustment of the drug is carried out with an interval of 2 to 4 weeks .

Radioactive iodine can be used in the treatment of distant metastasis of differentiated thyroid cancer after performing thyroidectomy in such patients . The possibilities of chemotherapy for thyroid cancer are limited, and its purpose is most appropriate for inoperable cancer, treatment of disseminated forms and undifferentiated thyroid cancer.

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