Many are afraid of getting cancer, and quite rightly so. This disease is dangerous and merciless. Death due to cancer is in second place, second only to deaths from heart disease. Sometimes doctors diagnose "neoplastic process". What this means is not clear to all patients. Some even think it's 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 tissue of the body, do not make themselves felt for a long time, which makes treatment very difficult and worsens the prognosis. This article discusses the causes of cancer, the features of its development and methods of treatment.
Etiology of tumors
Neoplastic processes are otherwise called neoplasia, which means “new growth”. A more familiar term for this phenomenon is a tumor, which means pathological, excessive, uncontrolled growth of atypical cells, capable ofinfect any tissue in the body. The neoplastic process can begin with a mutation in one cell, but according to the accepted international system, it differentiates only when 1/3 of all cells of an organ loses their previous characteristics and enters a new state. Thus, the beginning of the formation of cancer cells is only a prerequisite for the development of the disease, but it is not yet considered as such. In the vast majority of cases, the neoplastic process begins in one place. The tumor that develops there is called primary. In the future, pathological changes affect the work of all human organs, and the disease becomes systemic. Consider the characteristics 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, which are not associated with the neoplastic process and are a response to the commands that the body gives it. Thus, reproduction (division) of a normal cell begins only when it receives an appropriate signal from outside. They are the presence in the nutrient medium of up to 20% of serum and growth factors. These factors, using specific receptors, transmit an “order” to the cell for replication (synthesis of a daughter molecule) of DNA, that is, for division. The cancer cell doesn't need orders. She shares as she pleasesunpredictable and out of control.
The second immutable law for a normal cell is that it can start dividing only if it is attached to some extracellular matrix, for example, for fibroblasts it is fibronectin. If there is no attachment, even if there are orders from outside, division does not occur. A cancer cell does not need a matrix. After the transformations that have taken place in her, she generates her own "commands" to the beginning of the division, which she strictly executes.
Number of divisions
Normal cells live, shall we say, in a friendly community of their own kind. This means that the division, growth and development of one of them does not infringe on the existence of the other. Interacting with each other and obeying the "orders" of cytokines (information molecules), they stop multiplying 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 too many of them have already formed, continue to multiply, crawl on top of each other, squeeze neighboring cells, destroy them and kill them. Cancer cells do not respond to the “orders” of cytokine growth inhibitors to stop dividing, and in addition, their reproduction is not stopped by adverse conditions arising from their activity, such as hypoxia, a lack of nucleotides. In addition, they behave very aggressively - they begin to interfere with the normal synthesis of he althy cells, forcing them to produce substances that are not necessary for them and necessary for themselves, thusthereby disrupting metabolic processes. In addition, cancer cells are able to penetrate into the bloodstream, 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. He althy cells also have their own lifespan, during which they carry out the number of divisions they are supposed to, gradually grow old and die. This phenomenon is called apoptosis. With its help, the body maintains the number of each type of cell it needs. Neoplastic processes are characterized by the fact that mutated cells "forget" the number of divisions that nature prescribed for them, 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 another one - a violation of differentiation, that is, specific cells that synthesize the necessary proteins may not form in tumors, and they begin to multiply before reaching maturity.
Neoangiogenesis
The unique property of cancerous tumors is their ability to very active angiogenesis, that is, to the formation of new blood vessels. In a he althy body, angiogenesis occurs to a small extent, for example, during the formation of scars or during the healing of foci of inflammation. Neoplastic processes greatly increase this function of the body, because if blood vessels do not appear in the overgrown body of tumors, then not all cancer cells will receivethe nutrients they need too. 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 an exact copy of it. Under certain factors, failures occur in its DNA, and during division, a “daughter” appears - a mutant with some new qualities. When it's her turn to divide, even more transformed cells appear. Neoplastic processes occur with the gradual accumulation of these mutations. The immortality of such cells and their departure from obeying the orders of the body leads to the emergence of more and more malignant variants and to the steady progression of tumor growth.
Reasons
The cell starts behaving 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 have been identified, caused by a hereditary anomaly of the following genes:
-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 in total.
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, disruptions in metabolic processes.
5. Oncoviruses. It is believed that there is a special type of virus that can trigger neoplastic processes. These include the herpes virus, papillomavirus, retrovirus and others.
Bad ecology, low-quality food, high psychological stress lead to the fact that mutant cells in people's bodies appear constantly, but the immune defense detects them and destroys them in time. If the immune system is weakened, abnormal cells remain alive and gradually become malignant.
Types of tumors
People often ask if a neoplastic process is cancer or not? There is no single answer to it. All tumors are divided into two categories:
-benign;
-malignant.
Benign are those in which cells can be differentiated and do not metastasize.
In malignant tumors, cells often completely lose their resemblance to the tissues from which they developed. These formations have rapid growth, the ability to infiltrate (penetrate into neighboring tissues and organs), metastasize and have a pathological effect on the entire body.
Benign tumors without propertreatments very often develop into malignant ones. There are such types of them:
-epithelial (do not have specific localization);
-epithelial tumors of the endocrine glands and integument;
-mesenchymal (soft tissues);
-muscle tissues;
-shells of the brain;
-organs of the nervous system;
-blood (hemoblasts);
-teratoma.
Development stages
Answering the question whether the neoplastic process is cancer or not, it should be said that in the pathogenesis of tumor development there is such a condition as precancer. There are two types:
-obligate (almost always turning into cancer);
-optional (not always turning into cancer). 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 stage is called initiation. At the same time, oncogenes appear in the cell (any genes that can turn the cell into a malignant one). The most famous oncogene is p53, which in the normal state is an anti-oncogene, that is, it fights the development of tumors, and when mutated, it causes them.
At the next stage, called promotion, these altered cells begin to divide.
The third stage is called pre-invasive. At the same time, the tumor grows, but does not yet penetrate into neighboring organs.
The fourth stage is invasive.
The fifth stage is metastasis.
Signs of 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-rays, 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 seals, development in the ear - hearing loss, in the spine - difficulty 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 the blood vessels in them. This is what causes the appearance of blood in the secretions, and not only from the genitals. So, blood in the urine is observed when a neoplastic process of the kidney, bladder or urinary tract develops, blood in the feces may indicate the onset of cancer in the intestines, blood from the nipple - a tumor in the mammary gland. Such a symptom should definitely cause anxiety and prompt an immediate visit to the doctor.
Another early symptom is the so-called small sign syndrome. Its main feature is a wide variety of manifestations. Common are complaints of patients about weakness, fatigue, sudden temperature fluctuations, inexplicable irritation or, conversely, indifference to everything, loss of appetite, and on this basis, emaciation.
In subsequent stages, symptoms of intoxication appear, as well as a change in skin color to icteric with paleshade, decreased skin turgor, cancer cachexia.
With neoplasms in the brain tissues, 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, the neoplastic process in the occipital part is manifested by the appearance of visions in the patient, a violation of color perception. During the process in the temporal region, visions are not observed, but there are auditory hallucinations. A tumor in the frontal lobe is characterized by mental disorders of the patient, a violation of his speech, and in the parietal region by a violation of motor functions and sensitivity. Symptoms of damage to the cerebellum - frequent vomiting and terrible headaches, and damage to the brain stem - difficulty in swallowing, breathing disorders, malfunctions of many internal organs.
In the last stages, all cancer patients experience excruciating pain, which can only be stopped with narcotic drugs.
Diagnosis
To establish the diagnosis of "neoplastic process", the patient undergoes a series of tests and a comprehensive examination is prescribed. Recently, tests for oncomarkers 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 tumor marker PSA indicates that the subject has begun a neoplastic process in the prostate gland, and the tumor marker CA-15-3B indicates a neoplastic process in the mammary gland. The downside of the analysis for tumor markers is that they can increase in the blood and in other diseases not associated with neoplastic processes.
To clarify the diagnosis, the patient is given the following tests:
-blood, urine tests;
-ultrasound;
-CT;
-MRI;
-angiography;
-biopsy (this is a very important test that not only determines the presence of a cancerous tumor, but also the stage of its development).
If bowel cancer is suspected, do:
- analysis of feces for the presence of occult blood in it;
-fibrosigmoscopy;
-rectomonoscopy.
Neoplastic process of the brain is best detected by MRI. If this type of diagnosis is contraindicated for a patient, a CT scan is performed. Also for brain tumors:
-pneumoencephalography;
-electroencephalogram (EEG);
-radioisotope scan;
-spinal tap.
Treatment
If children are affected, 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 affectswhole body);
-radiation and radiotherapy (affects directly on the tumor, may affect neighboring he althy areas);
-hormone therapy (designed to produce hormones that prevent tumor growth or destroy it, for example, the neoplastic process of the prostate 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 p53 gene with a normal one);
-surgical operation (can be performed to remove the tumor or to reduce the suffering of the patient by reducing the overgrown inoperable tumor to neighboring tissues).
Forecast
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 the development of the tumor is detected in the early stages. But even in the late stages of detection with intensive care, children can be completely cured.
In adults, a favorable prognosis for the first stage of the tumor is 80% or more. At the third stage, a favorable outcome of treatment is observed in 30% -50% of cases (depending on the localization of the formation and the characteristics of the body of each person). At 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. Worst prognosis for prostate and brain cancer.
