The hormone calcitonin

Calcitonin – what is it?

Calcitonin is a thyroid hormone secreted by special cells. These cells are often in close proximity to the follicles why they were previously called parafollicular cells. C-cells are neuroendocrine in origin and are formed in the pancreas in the process of fetal development of the human body. Synthesis of calcitonin is the primary function of C-cells.

The function of calcitonin is not yet fully understood, this distinguishes it from other thyroid hormones. The number of C-cells secreting calcitonin, significantly less than a - and C - cells within follicles of the gland. If the hormones T3 and T4 are examined to determine organ function, the value of calcitonin blood was used for other purposes.

Calcitonin tumor marker is its major role in modern medicine!

In various textbooks and manuals, the hormone calcitonin is considered as an antagonist to parathyroid hormone – parathyroid product (or parathyroid) glands. The value of parathyroid hormone is to activate special cells called osteoclasts. The latter under the action of this hormone destroy bone tissue, where it releases calcium into the bloodstream. Another function of parathyroid hormone – increased reabsorption of calcium ions in the renal tubule from the primary urine. Parathyroid hormone also stimulates the conversion of vitamin D to its active form – calcitriol, which provides transport of calcium ions from the small intestine into the blood. Thus, the final result of the work of parathyroid hormone is to increase calcium level in plasma, while calcitonin has the opposite effect.

In their activity of calcitonin of parathyroid hormone is much weaker in this regard, one can argue that the exchange of calcium in the body is regulated by these two hormones. In this complex process, in addition to parathyroid hormone and calcitonin, involved vitamin D and many other compounds.

C-cells of thyroid gland synthesize calcitonin in very small amounts, so its concentration in the blood in very low rate. Insignificant amount this hormone can be produced in the intestine. In this article, we consider calcitonin as a tumor marker, which is used in the diagnosis of a formidable tumor from the tissue of the thyroid gland medullary cancer.

Calcitonin is a tumor marker that allows you to confidently make the diagnosismedullary cancer even in its early stages

A blood test for calcitonin

The concentration of calcitonin, it is now possible to determine in many laboratories for this purpose, use of various equipment. The most reliable information about the content of this hormone can be obtained by using the analyzers 3 generation, based on immunochemiluminescence method. The more common 2nd generation analyzers utilizing immunoassay methods are cheaper but have a serious drawback – a significant error results. Their use may lead to inaccuracies in diagnosis and subsequent treatment of patients.

If the blood calcitonin is the main interest rate – ask the lab what method to perform the analysis.

From C-cells of thyroid follicles may develop very dangerous malignant tumor – cell carcinoma, or medullary cancer. A feature of this tumor is relatively slow, but steady growth. Over time, medullary carcinoma metastasizes to the lymph nodes located in the neck area and mediastinum, with blood metastasis can also enter the lungs, liver, bones and even the brain. Treatment With cell carcinoma represents a significant challenge, since the tumor does not respond to antitumor chemotherapy and radiation therapy. Slightly to influence the carcinoma-cells can only antitumor agents from inhibitors of kinases. The only effective treatment for this type of cancer – surgery in the early stages of the process. This is the only method that gives a chance of recovery with early diagnosis of cancer.

As cell carcinoma grows from cells that produce calcitonin, its content in the blood increases sharply at the early stages of cancer. That is why the content of this hormone so interested in endocrinologists and surgeons. The measurement of calcitonin is the most reliable and early method of determining medullary cancer, helping them to save thousands of lives.

Annually throughout Russia is registered about 100-150 new cases of C-cell carcinoma of the thyroid gland. Statistical studies showed that in 16 densely populated regions of the European part of Russia for the year will be billed about 40 diagnoses of medullary cancer.

Among allcases of thyroid tumors, the most dangerous are anaplastic and medullary forms. If for anaplastic cancer is not yet developed effective ways of treatment With cell carcinoma is very treatable with early diagnosis. And help can only blood test for calcitonin.

In 2012, the European teleologically Association recommendation was added indicating the need for a single definition of calcitonin in all patients with nodes in the thyroid gland. This analysis does not necessarily run every year, retesting in the case of the first normal result is assigned only in the case that was registered by the new nodes.

According to the results of large studies conducted at international level, when determining the level of calcitonin in all patients with thyroid nodules in 1 case out of 300 detected by anyone not previously suspected medullary carcinoma.

This fact made the European endocrine community to lean to the view that the financial costs of holding 300 studies will be justified if at least one of them will allow to establish the presence of medullary cancer. At the same time, the American Association of trialogos yet believes that economically, such a mass study of calcitonin is not justified. This applies only to the financial part of the question, the clinical value of this method for anybody does not cause doubts.

What is the norm of calcitonin?

When interpreting the results of a blood test for calcitonin is necessary to consider that the lower limit of this hormone does not exist. Even its zero concentration in the normal range. To exclude or confirm the diagnosis it is important that the level of calcitonin was higher than those values defined as the upper limit of normal. This limit is individual for each specific analyzer used, and each set of reagents.

There is no point in this article to indicate the normal level of calcitonin, as they significantly vary in different laboratories in connection with the use of completely different analyzers. Therefore, the concept of the norm becomes very vague. In modern laboratories, the indicators normal values are indicated on the same form which is given the result of the analysis.

When calcitonin is elevated

Any even minorthe increase in the content of calcitonin, is a major cause for in-depth examination of the patient by professionals with experience in the diagnosis and treatment of cell carcinoma.

It is believed that the likelihood of a medullary carcinoma of calcitonin at a concentration above 100 PG/ml is close to 100%. There is a direct relationship between the degree of increase of this hormone and cancer, as well as the presence or absence of distant metastasis.

If the results of fine-needle biopsy of the nodes in the thyroid gland are benign, but the hormone levels are elevated, is the advantage of the second analysis, as the probability that the study results wrong, very small. In the case of a significant exceeding of the upper limit of normal (greater than 100 PG/ml), the patient completely remove the thyroid gland and all adjacent lymph nodes, to exclude the presence of regional metastasis. Therefore, the definition of calcitonin – a very serious analysis, and the results should be as accurate as possible.

It should be noted that the occurrence of medullary cancer contributes to genetic predisposition. Almost 50% of patients With cell carcinoma, the children also get sick. Sometimes you have to remove the thyroid gland in children aged 5-7 years and even younger to prevent the growth of malignant cells. In such cases, even the slight increase of calcitonin suggests that the doctor is doing everything right.

There are difficult situation, when the hormone levels slightly higher than normal, i.e. below 100 PG/ml, but above the upper border of normal values. This result can be said to be a very small tumour, and about her absence. In any case, increased levels of the hormone need to contact a specialized endocrinology center for additional testing.

Among them may be:

• Fine needle puncture site with the histological analysis of the tumor and determination of calcitonin in washout of the needle;
• Stimulated test study of calcitonin in the blood after administration of calcium gluconate.

The above information allows us to derive the following provisions:

• Calcitonin is a tumor marker used to diagnose medullary cancer;
• A blood test for the hormone calcitonin must pass all patients with nodes in the thyroid gland;
• The analysis should be taken to a specialized laboratory that conducts research on the chemiluminescent analyzer of the third generation;
• Any increase in the level of calcitonin in the blood should be a reason for treatment in a specialized centerendocrinology.