Cancer of a thyroid gland
Cancer of a thyroid gland – the malignant nodal education developing from a follicular or parafollicular (S-cages) epithelium of a thyroid gland. Distinguish follicular, papillary, medullary, anaplastichesky cancer and a lymphoma of a thyroid gland, and also its metastatic defeats. Clinically cancer of a thyroid gland is shown by swallowing difficulty, feeling of a sdavleniye and a sore throat, an osiplost, cough, weight loss, weakness and perspiration. Diagnostics is carried out according to ultrasonography, MRT and a stsintigrafiya of a thyroid gland. However the main criterion is detection of cancer cells in the material received at a tonkoigolny biopsy of gland.
Cancer of a thyroid gland
Cancer of a thyroid gland – the malignant nodal education developing from a follicular or parafollicular (S-cages) epithelium of a thyroid gland. Frequency of prevalence of cancer of thyroid gland makes about 1,5% of all malignant tumors of other localizations. Cancer of a thyroid gland meets at women after 40-60 years more often (by 3,5 times more often than at men). After the Chernobyl accident the frequency of cancer cases of a thyroid gland considerably increased, especially among children whose thyroid gland is much more sensitive to accumulation of radioactive iodine. In the absence of influence of radiation the incidence of cancer of a thyroid gland increases with age.
Features of a course of cancer of thyroid gland is the stertost of a clinical picture, painlessness of the palpated knots, early metastasis in lymph nodes and other bodies (at some forms of cancer). Good-quality nodal formations of a thyroid gland meet considerably more often malignant (90%-95% and 5%-10% respectively) that demands performing careful differential diagnostics.
Reasons of development of cancer of thyroid gland
Researches confirm that cancer of a thyroid gland develops in 80% of cases against the background of already available craw, and its frequency is 10 times higher in areas, endemic on a craw.
Also development of cancer of thyroid gland is promoted by a number of factors of the increased risk:
- existence of chronic inflammatory processes in a thyroid gland;
- long inflammatory or tumoral processes of the sexual sphere and mammary glands;
- hereditary predisposition to dysfunction and tumors of endocrine glands;
- the general or local (areas of the head and a neck) the x-ray or ionizing radiation, especially at children's and teenage age;
- the adenoma of a thyroid gland which is regarded as a precancer disease;
- number of hereditary genetic states (family polyposes, Gardner's syndrome, Kouden's disease, family forms of a medullary carcinoma of a thyroid gland, etc.);
- the states connected with change of hormonal balance in a female body (a climax, pregnancy, a lactation).
More often in development of cancer of thyroid gland the mutual combination of a number of factors plays a role.
Classification of cancer of thyroid gland
According to the international classification of tumoral formations of a thyroid gland are allocated: epitelialny tumors of good-quality and malignant character, and also neepitelialny tumors. In histologic forms allocate the following types of cancer of thyroid gland: papillary (about 60-70%), follicular (15-20%), medullary (5%), anaplasticheskiya (2-3%), mixed (5-10%), a lymphoma (2-3%).
The criterion of prevalence of a tumor in iron and existence of metastasises in lymph nodes and the remote bodies where is the cornerstone of classification of cancer of thyroid gland by the international TNM system:
T - prevalence of cancer in a thyroid gland
- T0 — at operation of existence of primary tumor in a thyroid gland is not revealed
- T1 — the tumor in the largest diameter to 2 cm which is not extending for borders of a thyroid gland (i.e. not sprouting in its capsule)
- T2 — a tumor> 2 cm, but
- T3 — a tumor> 4 cm in the largest diameter, not extending for borders of a thyroid gland or a tumor of smaller diameter, with germination in its capsule
- T4 — this stage of cancer of thyroid gland is divided into 2 substages:
- T4a — the tumor having any size with germination of the capsule of a thyroid gland, hypodermic soft fabrics, throats, tracheas, a gullet or a returnable guttural nerve
- T4b — a tumor with germination of a prevertebral fastion, a carotid or zagrudinny vessels;
N - existence or lack of regionarny metastasises of cancer of thyroid gland
- NX — tumor metastasis cannot be estimated at cervical lymph nodes
- N0 — regionarny metastasises are absent
- N1 — are defined regionarny metastasises (in paratrakhealny, pretrakhealny, prelaringealny, side cervical, zagrudinny lymph nodes);
M – existence or lack of metastasises in the remote bodies
- MX — the remote metastasis of a tumor cannot be estimated
- M0 — the remote metastasises are absent
- M1 — are defined the remote metastasises
Classification of cancer of thyroid gland by the TNM system is used for a stadirovaniye of a tumor and forecasting of its treatment.
In development of cancer of thyroid gland allocate four stages (from most to the least favorable):
- The stage of I – a tumor is located locally, the capsule of a thyroid gland is not deformed, metastasises are absent
- IIA stage - the single tumor deforming gland or multiple knots without metastasises and deformation of the capsule
- IIB stage – existence of a tumor with unilateral metastatic lymph nodes
- Stage of III – the tumor sprouting the capsule or squeezing the next bodies and fabrics, and also existence of bilateral damage of lymph nodes
- Stage of IV – a tumor with germination in surrounding fabrics or bodies, and also a tumor with metastasises in the nearest and (or) remote bodies.
Cancer of a thyroid gland can be primary (if the tumor initially arises in gland) or secondary (if the tumor sprouts in gland from the next bodies).
Types of cancer of thyroid gland
Papillary cancer (carcinoma) of thyroid gland makes up to 70% and more all cases of malignant new growths of a thyroid gland. Microscopically papillary carcinomas have multiple sosochkoobrazny ledges, as defined their name (Latin of "papilla" - a nipple). The tumor develops extremely slowly, arises in one of shares of glands more often, and bilateral defeat occurs only at 10-20% of patients. Despite slow growth papillary cancer of a thyroid gland often spreads in cervical lymph nodes. The forecast at papillary cancer of a thyroid gland is rather favorable: most of patients have high percent of 25-year survival. Considerably cancer metastasis in lymph nodes and the remote bodies burdens the forecast, the age of patients is more senior 50 and 25 years, the tumor size> 4 cm are younger.
Follicular cancer (carcinoma) of thyroid gland – the second for emergence frequency the type of a malignant tumor of a thyroid gland which is found in 5-10% of cases. Develops from the follicular cages making normal structure of a thyroid gland. Pathogenetic developing of follicular cancer of thyroid gland is connected with shortage of iodine in food. In most cases this type of cancer does not extend out of gland limits, metastasises in lymph nodes, bones and lungs meet less often. The forecast in comparison with a papillary morphological form of cancer is less favorable.
Anaplastichesky cancer of a thyroid gland – the rare form of a malignant tumor tending to rapid growth, defeat of structures of a neck and distribution in an organism with extremely adverse forecast for life. Usually develops at elderly patients against the background of it is long an observed nodal craw. Rapid growth of a tumor with violation of functions of structures of a sredosteniye (suffocation, difficulty when swallowing, a dysphonia) and germination of nearby bodies leads to development of a lethal outcome within a year.
Medullary cancer of a thyroid gland (carcinoma) – the form of a malignant tumor developing from parafollicular (S-cells) of gland and a component about 5% of cases. Even before detection of primary tumor in a thyroid gland can spread in lymph nodes, a liver and lungs. In blood of the patient the rakovoembrionalny anti-gene and the raised calcitonin synthesized by a tumor are defined. The course of medullary cancer of thyroid gland more aggressive in comparison with follicular and papillary cancer, with early development of metastasises in nearby lymph nodes and distribution on muscles, a trachea, easy and other bodies.
Lymphoma of a thyroid gland – the tumor developing from lymphocytes against the background of an autoimmune tireoidit or independently. Bystry increase in the sizes of a thyroid gland with involvement of lymph nodes and symptoms of a sdavleniye of a sredosteniye is observed. The lymphoma will well respond to treatment the ionizing radiation.
Metastasises of malignant tumors of other localizations in a thyroid gland meet seldom. Metatstatichesky damage of a thyroid gland is observed at a melanoma, cancer of a stomach, mammary gland, lungs, intestines, a pancreas, lymphoma.
Symptoms of cancer of thyroid gland
Usually complaints of patients are connected with emergence of nodal educations in a thyroid gland or increase in cervical lymph nodes. In process of growth of a tumor symptoms of a sdavleniye of structures of a neck develop: voice osiplost, swallowing violation, short wind, cough, suffocation, pains. At patients perspiration, weakness, a loss of appetite, loss of weight is noted.
Children have a course of cancer of thyroid gland rather slow and favorable. At young patients predisposition to limfogenny metastasis of a tumor is noted, more senior persons – to germination of surrounding bodies have necks. At elderly patients the general signs are more expressed, rapid progressing of pathology, prevalence of high-malignant forms of cancer of thyroid gland is observed.
Diagnosis of cancer of thyroid gland
At a palpation of a thyroid gland the knots of a dense consistence soldered to surrounding fabrics are found single or multiple, smaller or bigger size; limited mobility of gland, surface bugristost; increase in lymph nodes.
Carrying out a stsintigrafiya of a thyroid gland maloinformativno in respect of differential diagnostics of good-quality or malignant nature of a tumor, however, allows to specify prevalence degree (stage) of tumoral process. During the research the entered intravenously radioactive iodine collects in knots of a thyroid gland and surrounding fabrics. The knots absorbing a large amount of radioactive iodine are determined by skanogramma as "hot", smaller – "cold".
On ultrasonography of a thyroid gland the size and the number of knots in a thyroid gland comes to light. However on ultrasonography good-quality educations and cancer of a thyroid gland are difficult distinguishable that demands use of additional methods of visualization of gland.
By means of a magnetic and resonant tomography differentiation of cancer of thyroid gland from good-quality nodal education is possible. The computer tomography of a thyroid gland gives the chance to specify a disease stage. The main method of verification of cancer is the tonkoigolny biopsy of a thyroid gland with the subsequent histologic research of a bioptat.
Anemia, acceleration of SOE, change of function of a thyroid gland (increase or decrease) are characteristic of patients with cancer of a thyroid gland. At a medullary form of cancer in blood calcitonin hormone level increases. Increase in level of protein of a thyroid gland of a tireoglobulin can testify to a recurrence of a malignant tumor.
Cancer therapy of a thyroid gland
At the choice of a method of cancer therapy of a thyroid gland consider tumor type, a stage and the general condition of the patient. Today the endocrinology has several effective ways of fight against cancer of a thyroid gland in the arsenal. Treatment can include operation, therapy by radioactive iodine or hormones, chemotherapy, radiation. Use of a combination of two and more methods allows to reach high percent of treatment at cancer of a thyroid gland.
The most radical is carrying out surgical removal of a thyroid gland - a subtotal and total tireoidektomiya. At cancer of a thyroid gland of the I-II degree with localization of a tumor within one share are limited to its removal together with an isthmus and suspicious sites of other share. The expanded tireoidektomiya including removal of muscles of a neck, excision of a jugular vein of regionarny lymph nodes and fatty hypodermic cellulose is shown at the III-IV stage of cancer of thyroid gland.
In addition to operation the course of treatment the radioactive I-131 iodine (from 50 do150 mCi) destroying metastasises of cancer of thyroid gland and the remains of tireoidny fabric after surgery is appointed. Therapy by radioactive iodine is most effective at metastasises of cancer of thyroid gland in lungs and can lead to their total disappearance.
Emergence of a recurrence of a tumor is controlled by a research of level of a tireoglobulin in blood. At the progressing metastasis of cancer of thyroid gland external radiation is used. Beam and chemotherapy are used for palliative treatment of widespread tumoral process.
After operation for cancer of a thyroid gland the carrying out periodic repeated inspection for an exception of a recurrence and metastasises of a tumor including a X-ray analysis of lungs, ultrasonography of a thyroid gland, a stsintigrafiya, a research of level of a tireoglobulin in blood, etc. is necessary. After a partial or total tireoidektomiya reception of tireoidny hormones (tiroksin) is necessary for maintenance of concentration of TTG within the lower bound of norm and decrease in probability of a recurrence of cancer of thyroid gland.
The forecast at cancer of a thyroid gland
The forecast is defined by a stage of cancer of thyroid gland at which performing treatment, and also histologic structure of a tumor is begun. The probability of treatment of cancer of thyroid gland at early diagnosis and moderate degree of a zlokachestvennost of a tumor reaches 85-90%.
The unsatisfactory forecast is observed at a lymphoma and an anaplastichesky form of tireoidny cancer: the lethality within half a year from the beginning of a disease is near absolute to value. The course of medullary cancer which early spreads in the remote bodies differs in high degree of a zlokachestvennost.
Less aggressive on predictive value is follicular cancer of a thyroid gland, the most good-quality current have papillary and the mixed forms. The course of cancer of thyroid gland is more favorable at persons of mature age, less – at people is more senior 60 and 20 years are younger.
Prevention of cancer of thyroid gland
Broad prevention of cancer of thyroid gland assumes elimination of shortage of iodine due to the use of iodinated salt and seafood, carrying out radiological radiation of the head and area of a neck strictly according to indications. As an important part of prevention serves timely treatment of tireoidny pathology, dynamic observation at the endocrinologist of patients of risk groups: having pathology of a thyroid gland, living in the territory with yododefitsity, undergone radiation, having family cases of medullary cancer of thyroid gland.