Many are afraid of getting cancer, and rightly so. This ailment is dangerous and merciless. The death due to cancer is in second place, second only to deaths from heart disease. Sometimes doctors diagnose a "neoplastic process." What this means is far from clear to all patients. Some even think that this is something good, or at least not dangerous. In fact, such a diagnosis means the same tumor processes that are observed in cancer. They affect people of all ages, including infants, can develop in any organ and in any body tissue, for a long time they do not make themselves felt, which makes treatment very difficult and worsens the prognosis. This article discusses the causes of cancer, the features of its development and treatment methods.
Etiology of tumors
Neoplastic processes are also called neoplasia, which means “new growth”. A more familiar term for this phenomenon is a tumor, which means abnormal, excessive, uncontrolled growth of atypical cells that can affect any body tissue. The neoplastic process can begin with a mutation in one cell, but according to the accepted international system, it only differentiates when 1/3 of all cells of an organ lose their previous characteristics and transfer to a new state. Thus, the onset of cancer cell formation is only a prerequisite for the development of the disease, but it is not yet considered. In the vast majority of cases, the neoplastic process begins in one place. The tumor developing there is called primary. In the future, pathological changes affect the work of all human organs, and the disease becomes systemic. Consider the features of cancer cells.
Division
Our body is made up of millions of cells. They have characteristic differences in structure, which depends on the functions of the organ or tissue in which they are located. But they all obey a single law - to ensure the viability of the system as a whole. Throughout the life of each cell, successive cellular changes occur in it that are not related to the neoplastic process and are a response to the commands that the body gives it. So, the reproduction (division) of a normal cell begins only when it receives an appropriate signal from the outside. It is the presence in the nutrient medium of up to 20% of serum and growth factors. These factors, using specific receptors, transmit to the cell an “order” for replication (synthesis of a daughter molecule) of DNA, that is, for division. Cancer cell orders are not required. She shares, as she pleases, unpredictably and uncontrollably.
The second immutable law for a normal cell is that it can begin to divide only if it is attached to a certain extracellular matrix, for example, for fibroblasts this is fibronectin. If there is no attachment, even if there are orders from outside, division does not occur. The cancer cell does not need a matrix. After the transformations that took place in her, she generates her own “commands” to the beginning of the division, which she scrupulously executes.
Number of divisions
Normal cells live, say, in a friendly community of their own kind. This means that the division, growth and development of one of them does not impair the existence of the other. Interacting with each other and obeying the “orders” of cytokines (information molecules), they cease to multiply when the need for this disappears for the body. For example, the same fibroblasts divide until they create a dense monolayer and establish intercellular contacts. A specific neoplastic process is characterized by the fact that atypical cells, even if they have already formed too much, continue to multiply, crawl onto each other, squeeze neighboring cells, destroy them and kill them. Cancer cells do not respond to “orders” of cytokine growth inhibitors to stop dividing, and in addition, their reproduction does not stop unfavorable conditions arising from their activity, such as hypoxia, lack of nucleotides. In addition, they behave very aggressively - they begin to interfere with the normal synthesis of healthy cells, forcing them to produce substances that are not necessary for them and necessary for themselves, thereby disrupting metabolic processes. In addition, cancer cells are able to penetrate into the blood, move in its current through the body and settle in other tissues far from the primary focus, that is, metastasize.
Immortality
There is nothing eternal in the world. Healthy cells also have their own lifespan, during which they carry out the number of divisions laid down by them, gradually age and die. This phenomenon is called apoptosis. With its help, the body supports the number of each type of cell that it needs. Neoplastic processes are characterized by the fact that mutated cells “forget” the number of divisions prescribed by nature, therefore, having reached the final figure, they continue to multiply further. That is, they acquire the ability not to grow old and not to die. Simultaneously with this unique property, cancer cells acquire one more thing - impaired differentiation, that is, specific cells that do not synthesize the necessary proteins may not form in tumors, and they begin to multiply before they reach maturity.
Neoangiogenesis
A unique property of cancerous tumors lies in their ability to very active angiogenesis, that is, to the formation of new blood vessels. In a healthy body, angiogenesis occurs to a small extent, for example, with the formation of scars or with the healing of foci of inflammation. Neoplastic processes multiply this function of the body, because if blood vessels do not appear in the overgrown body of tumors, then not all cancer cells will receive the nutrients that they also need. In addition, they use blood vessels to move further through the body (to form metastases).
Genetic instability
When a normal cell divides, the daughter cell is obtained by its exact copy. Under certain factors, malfunctions occur in her DNA, and during division, a “daughter” appears - a mutant with any new qualities. When it comes to dividing, even more transformed cells appear. Neoplastic processes occur during the gradual accumulation of these mutations. The immortality of such cells and their departure from obeying the orders of the body leads to the appearance of increasingly malignant variants and to a steady progression of tumor growth.
Causes
A cell begins to behave abnormally due to changes in its DNA. Why they occur while there is no exact answer, there are only theories according to which neoplastic processes can begin with varying degrees of probability.
1. Hereditary genetic predisposition. 200 types of malignant neoplasms caused by a hereditary anomaly of the following genes have been identified:
- responsible for the restoration of damaged DNA;
-regulating the interaction between cells;
- responsible for suppressing the development of tumors.
2. Chemicals (carcinogens). According to WHO statistics, they are responsible for 75% of cancer cases. Commonly recognized carcinogens are: tobacco smoke, nitrosamines, epoxides, aromatic hydrocarbons - more than 800 elements and their compounds.
3. Physical agents. These include radiation, radiation, exposure to high temperatures, injury.
4. Endogenous carcinogens. These are substances formed in the body during hormonal disorders, malfunctions in metabolic processes.
5. Oncoviruses. It is believed that there is a special type of virus that can trigger neoplastic processes. These include herpes virus, papillomovirus, retrovirus and others.
Poor ecology, poor-quality food, high psychological stresses lead to the fact that mutant cells in human organisms appear constantly, but the immune defense detects them and destroys them in time. If immunity is weakened, atypical cells remain alive and gradually become malignant.
Types of tumors
It is often asked whether the neoplastic process is cancer or not. There is no definite answer to it. All tumors fall into two categories:
- benign;
malignant.
Benign are those in which cells can be differentiated, and which do not give metastasis.
In malignant tumors, cells often completely lose their resemblance to the tissues from which they evolved. These formations have rapid growth, the ability to infiltrate (penetrate into adjacent tissues and organs), metastasize and have a pathological effect on the whole organism.
Benign tumors without proper treatment very often develop into malignant. There are such types of them:
-epithelial (do not have specific localization);
-epithelial tumors of the endocrine glands and integuments;
- mesenchymal (soft tissues);
muscle tissue;
shells of the brain;
organs of the nervous system;
blood (hemoblasts);
teratomas.
Developmental stages
Answering the question whether the neoplastic process is a cancer or not, it should be said that in the pathogenesis of the development of tumors, a condition such as precancer is observed. There are two types of it:
Obligatory (almost always turning into cancer);
- optional (passing into cancer is not always). An optional precancer can be called bronchitis of smokers or chronic gastritis.
Any neoplastic process does not develop instantly, but gradually, often starting with atypical changes in just one cell. This step is called initiation. In this case, oncogenes appear in the cell (any genes that can turn a cell into a malignant one). The most famous oncogen is p53, which in the normal state is an anti-oncogen, that is, it fights the development of tumors, and when it mutates, it causes them.
In the next step, called promotion, such altered cells begin to divide.
The third stage is called preinvasive. In this case, the tumor grows, but has not yet penetrated into neighboring organs.
The fourth stage is invasive.
The fifth stage is metastasis.
Signs of a neoplastic process
At the first stages, the pathology that has begun does not manifest itself in any way. It is very difficult to detect it even with such studies as ultrasound, X-ray, various tests. In the future, patients develop specific symptoms, the nature of which depends on the location of the primary tumor. So, its development in the skin or in the mammary gland is signaled by neoplasms and compaction, on the development in the ear - hearing loss, in the spine - difficulties in movement, in the brain - neurological symptoms, in the lungs - cough, in the uterus - blood discharge. When cancer cells begin to invade neighboring tissues, they destroy blood vessels in them. This is what causes the appearance of blood in the discharge, and not only from the genitals. So, blood in the urine is observed when a neoplastic process develops in the kidney, bladder or urinary tract, blood in the stool can indicate the onset of cancer in the intestine, blood from the nipple - about a tumor in the mammary gland. Such a symptom must necessarily cause anxiety and encourage immediate medical attention.
Another early symptom is the so-called small sign syndrome. Its main feature is a wide variety of manifestations. Common can be called complaints of patients about weakness, fatigue, sudden temperature spikes, inexplicable irritation or, on the contrary, indifference to everything, loss of appetite, and emaciation on this basis.
In subsequent stages, symptoms of intoxication appear, as well as a change in skin color to icteric with a pale tint, a decrease in skin turgor, and cancer cachexia.
With neoplasms in the brain tissue due to the fact that this organ is limited by the bones of the skull, and for a developing tumor, the space is very limited, and also due to the specificity of the functions of each part of the brain, the symptoms have characteristic features that allow differentiating localization. So, a neoplastic process in the occipital part is manifested by the appearance of visions in a patient, a violation of color perception. During the process in the temporal region of the vision is not observed, but there are auditory hallucinations. A tumor in the frontal lobe is characterized by mental disorders of the patient, impaired speech, and in the parietal region a violation of motor functions and sensitivity. Symptoms of cerebellar damage are frequent vomiting and terrible headaches, and brain stem lesions are difficulty swallowing, respiratory distress, and malfunctioning of many internal organs.
In the last stages, all cancer patients experience excruciating pains, which can only be stopped with narcotic drugs.
Diagnostics
To establish the diagnosis of "neoplastic process" the patient undergoes a series of tests and a comprehensive examination is prescribed. Recently, tests for tumor markers are often done. These are substances that can indicate the presence of a neoplastic process in the body, even in the early stages. In addition, many tumor markers are specific, their number increases only in the presence of tumor formations in any one organ. For example, the PSA tumor marker indicates that the patient has begun a neoplastic process of the prostate gland, and the CA-15-3B tumor marker has a neoplastic process in the mammary gland. The downside of the analysis for tumor markers is that they can increase in the blood and with other diseases that are not associated with neoplastic processes.
To clarify the diagnosis, the patient undergoes such tests:
-analysis of blood, urine;
Ultrasound
-KT;
MRI
angiography;
biopsy (this is a very important analysis, with which not only the presence of a cancerous tumor is determined, but also the stage of its development).
If you suspect intestinal cancer, do:
- analysis of feces for the presence of hidden blood in it;
-fibrosigmoscopy;
rectomonoscopy.
The neoplastic brain process is best detected by MRI. If this type of diagnosis is contraindicated to the patient, CT is performed. Also, for brain tumors:
- pneumoencephalography;
-electroencephalogram (EEG);
- radioisotope scanning;
spinal puncture.
Treatment
If the disease affects children, their treatment consists mainly of chemotherapy and radiation therapy, surgery is rarely performed. For the treatment of adults, all available methods are used that are appropriate at a particular stage of the neoplastic process and depending on its location:
chemotherapy (systemic treatment that affects the whole body);
-radiation and radiotherapy (has an effect directly on the tumor, may affect neighboring healthy areas);
-Hormone therapy (designed to produce hormones that inhibit the growth of the tumor or destroy it, for example, the neoplastic process of the prostate gland can be stopped by a decrease in testosterone levels);
-immunotherapy (positive effect on the whole body);
gene therapy (scientists are trying to replace the mutated gene with the normal p53 gene);
-surgery (can be performed to remove the tumor or to reduce the suffering of the patient by reducing the overgrown inoperable tumor on adjacent tissues).
Forecast
A neoplastic process is not a sentence. In children, due to the fact that their young body is able to recover quickly, the prognosis is favorable in 90% of cases if tumor development is detected in the early stages. But even in the later stages of detection with intensive care, children can be completely cured.
In adults, a favorable prognosis in the first stage of the tumor is 80% and higher. At the third stage, a favorable treatment outcome is observed in 30% -50% of cases (depending on the localization of formation and the characteristics of the body of each person). In the fourth stage, according to statistics, from 2% to 15% of patients after therapy live 5 years or more. These numbers also depend on the location of the tumor. Least favorable prognosis for prostate and brain cancer.