See also: Cancer (homonymy)
The cancer is a Maladie characterized by a cellular proliferation abnormal and anomic within a normal fabric of the organization. These cell S derives very from same a clone, cell initiating of the cancer which acquired certain characteristics enabling him to divide indefinitely. During the evolution of the disease, certain cells can migrate of their place of production and form metastasis S.
Cancer is a general term indicating any disease for which some cell S of the human body divide in an uncontrolled way. The new resulting cells can form a malignant Tumeur (a neoplasm ) or be propagated through the body.
Great types of cancers:One generally distinguishes:
- the Carcinomes: cancer of a epithelium, i.e. a surface only made up of cells
- the Sarcomes: cancers proliferating in fabrics " Of support " like the Os.
- the hematopoietic cancers: cancer of the blood cells.
One classifies them according to the touched bodies, with for example standard of cancer:
- the Breast cancer
- the Cancer of the colon: cancer of the Colon and, near, that of the Rectum
- the Cancer of the pancreas
- the multiple Myélome: cancer of the osseous Marrow
- the Leukemia S: cancers of the Blood
- the Sarcome de Kaposi: cancer of the Blood-vessels
- Lymphoma S: Disease of Hodgkin and Lymphoma non-hodgkinien.
- the Cancer of the testicles
The Oncologie (or cancerology ) is the medical speciality of study, diagnosis and treatment of cancers. It is practiced by doctors oncologists or cancer specialists. Those can be according to their speciality chimiothérapeutes or radiothérapeutes .
Because of an negative image on the forecast near the public, cancer has many synonyms employed by the doctors: malignant Tumor , neoplasy , neoplasm , polymitose , carcinome …
Certain terms are more popular: tumor , crab …
Cancers were already described in Egyptian writings towards -3500. It is Hippocrates which gave the first definition of the disease, called then “ carcinome ” or “ squirre ”: a Tumeur (swelling) lasts, not-inflammatory, tending to repeat and spread until death.
The comparison of the national statistics is delicate, because detection and classifications varied according to the times and the countries. Thus, in France, the term “causes environmental” refers to the chemicals and pollution…, whereas in English, that refers to all that surrounds the man and, in a general way, all the exogenic factors, i.e. the Sun, the alcohol, the Tabagisme, the number of Grossesse S…
The full number of the death by cancer in France was, in 1997, of 146.705 , that is to say approximately 241 deaths for 100.000 inhabitants. It is the second cause of mortality after the cardiovascular diseases. In 2000: 278000 people were reached of a cancer and 150.000 died about it.
Cancers of the higher aérodigestives ways account for 15% of cancers (in majority, cancers of the Larynx).
France is sometimes presented as being the country having longest survival after cancer. But concerning survival at 5 years after the diagnosis, it would be the second in Europe behind Sweden, with approximately 52% of survival (63% for the women, 44% for the men). That hides great disparities according to cancers. One reaches chances of survival of 95% for the cancer of the thyroid one; at the men, one reaches 80% of survival at 5 years for the cancer of the prostate, and almost 100% for cancers of the testicles, and, at the women, 85% for breast cancer between 15 and 44 years, but 78% beyond 75 years. On the other hand, deep cancers are diagnosed more tardily and are very mortals: cancer of the pancreas (10% of survival), of the lung…
Quality of the care: rate of survival and surmortalityThe rate of survival also depends on the age. Five years after the diagnosis, 70% of the 15-45 years survive. Whereas only 39,4% of the cancerous patients 75 years old survive more than 5 years… knowing that being given the risk of metastases, one does not speak about cure for a cancer, but about remission (see Évolution further).
Pour to estimate the effectiveness of tracking and the care, one uses the rate of survival and the surmortality at a certain duration after the diagnosis.
Rate of survival
For a group of people at whom one diagnosed a cancer, one can distinguish those dead from the continuations of their cancer, and those dead of another thing. The surmortality at one duration T (for example 10 years) related to cancer is the probability of dying of the only fact of cancer during the duration T which follows the diagnosis.
The problem of the evaluation of this mortality is that it would be necessary to know the causes of all the deaths of the people which one diagnosed a cancer, which is impossible. Another estimate is thus used; for a group of people of the same sex and same age, one uses “relative survival”, i.e. the relationship between:
- probability of survival after a time T of the group of people which one diagnosed a cancer, and
- probability of survival with T of a group of people not having cancer, of the same age and of the same sex.
The studies show a surmortality from approximately 2% beyond 10 years after the diagnosis in the developed countries, which points the irrationality of the segregation that the patients undergo having had a cancer on behalf of the insurances and of the banks (surtaxes, refusal of loan…).
The results hereafter result from the Cancers document - long-term Forecasts of the Inserm.
The Eurocare study is leaning on a score of European countries for cases diagnosed during three periods (the patients studied during one period train a “troop”): 1978 - 1985, 1985 - 1989 and 1990 - 1994. This study does not distinguish the stage from the diagnosis.
The study étasunienne SEER was interested at the stage of cancer at the time of its diagnosis, according to three categories:
- localized tumor;
- tumor having a regional development (ganglionic);
- tumor having a remote development (metastasis).
Cancer in the childThe children represent less than 1% of the cases of cancer; in the developed countries, they are cured in two thirds of the cases.
In France, one counts each year (new cases):
- 450 leukemias;
- 300 cerebral tumors;
- 190 lymphomas (including 56% of lymphomas non-hodgkiniens between 2 and 3 years).
There exist many factors predisposing with cancer: they are called carcinogenic , carcinogenic or cancerogenic . The study of these factors is called carcinogenesis.
They can be:
- Genetic S, i.e. to have a hereditary component (case of some breast cancers);
- Pollution: its exact role is difficult to specify;
- Food: obesity supports many cancers. The regular consumption of fruit and vegetables decreases the risk of many cancers. Alcohol, finally, supports cancers of the throat, the esophagus and the liver;
- Radiation S (without forgetting the role of the Sun: it is thus important to use the sun lotions correctly during an exposure prolonged to the sun because that increases considerably the cancer risk of the Peau) because of the Ultraviolets;
- infections by certain germs;
It is necessary to note the particular role of the Tabac which is an important risk factor for various cancers (respiratory tracts, ORL, Vessie).
According to the last report/ratio 2007 of the Medical college, the Tabac remains the leading cause of cancer. Then the alcohol comes. The other causes are the Surpoids and the insufficiency of Physical exercise, then the professional exposures and the hormonal treatments of the Ménopause of the woman. Only 1% of the deaths are related to the Pollution. Finally, 50% of the origins of cancer remain still unexplained.
Biology of the malignant tumors
Genetics and cancer
Cancers are genetic pathologies i.e. they originate in a quantitative and/or qualitative modification of our genes. As they are somatic genetic deteriorations which are present only in sick fabric, the majority of cancers are thus not hereditary. Family cancers (10% of human cancers) are associated with a deterioration constitutional (or germinal) of a gene. This deterioration is thus present in all the cells of our organization, gamètes included. It can be transmitted to the descent.
There are three main categories of genes associated with cancerous pathologies: the Oncogène S, the genes suppressors of tumors and genes of repair of the DNA.
- the Oncogène S (also called proto-oncogenes or conceive) are the positive regulators of the cellular proliferation. They become hyperactive and their modification is dominant because it is enough that one of the two copies of the Gène is modified. One identified currently more than 100 Oncogène S. most known are the Gène S Ha-ras, myc, or abl.
- the second category includes/understands the genes suppressors of tumors which are negative regulators of the cellular proliferation (brakes). The two copies of these genes are inactivated in cancers.
- the third category corresponds to genes of the multiple systems of repair which are able to detect and to repair the lesions of DNA which modified oncogenes or the genes suppressors of tumor. These systems of repair are also inactivated in the cancer cells.
The cellular transformation
The cellular transformation corresponds in the passing of a normal cell Eucaryote towards a state cancer patients. Not to confuse with the bacterial transformation which is a completely different phenomenon.
Contrary to genetic pathologies like the mucoviscidose, the myopathies or certain hemophilia which is monogenic pathologies (only one gene is generally faded), cancer is a multigenic pathology. Each cancer originates in the deterioration from 10 to 20 genes. These deteriorations occur successive manners, each one of them supporting the following one (see framed). This continuation of deteriorations generally occurs on a very long chronological beach (5 to 20 years). This continuation of deterioration is not random and for each type of cancer, one could highlight I) a certain specificity of faded genes and a II) chronology in the development of the events In cancers of the colon, this succession of events first of all includes/understands (inter alia) the inactivation of the gene suppressor of tumor APC, then a change of the oncogene Ha-ras followed by the inactivation of the gene suppressor of tumor p53. There are other events which remain to be identified. The essential point is the specificity of faded genes and their chronology. In another type of cancer, the implied genes and the chronology are completely different. APC is faded only in cancers of the colon and never in cancers of the skin. On the other hand the deterioration of p53 is more ubiquitaire and can be found in practically all the types of cancers. In the cancer of the skin contrary to the cancer of the colon, the deterioration of the gene p53 is one of the first events. This very great genetic diversity is at the base of the heterogeneity of cancerous pathology. Inside even of a particular type of cancers like bronchial cancer, exists several sub-types (bronchial cancer with small cells, adenocarcinomist, bronchial cancer with large cells, etc) each one being associated with particular genetic deteriorations. The situation is identical for other cancer like the center, the stomach or the skin, each body which can be associated with several types of cancers according to the histological type with the cell having been in the beginning with pathology.
Origin of cancers
Surroundings 15% of human cancers can be associated with infectious agents. That can be viruses (HBV and cancer of the liver, HPV and cancer of the cervix, EBV and lymphoma of Burkitt), more rarely of the bacteria (Helicobacter and gastric cancer) or more rarely of the parasites (Schistosomes and cancer of the liver). In all these cases, in addition to the infection, one also finds deteriorations of oncogenes or genes suppressors in the tumors. The infectious agent does not intervene qu `with a stage of the process of cellular transformation.
The origin of deteriorations which modify the Oncogène S and the genes suppressors is multiple. One generally classifies them in two main categories, exogenic and endogenous.
- the exogenic origin corresponds to all the environmental exposures to which an organization is subjected. That goes from the tobacco to the ultra-violets of the sun while passing by asbestos, radiations gamma, the alcohol and of many other substances to which an individual is exposed voluntarily or involuntarily. They can act directly on the level of our DNA and cause deteriorations like certain molecules in the tobacco or the ultraviolet ones or cause inflammatory states supporting the cancerous appearance of cells (alcohol).
- deteriorations of endogenous origin are caused partly by molecules resulting from our metabolism like the reactive species with oxygen. Each day our DNA sudden of the million aggressions on behalf of these molecules but in the very large majority of the cases, those are repaired in a very effective way. Nevertheless, it is enough to a failure in the repair of an important gene to engage or continue a process of transformation cellular. Recent work (2007) suggests that the systems of repair of the DNA have an effectiveness which decreases with the age.
In 2000 R. Weinberg and D. Hanahan suggested that the cellular transformation passes by the acquisition of at least six properties:
- Independence with respect to the signals stimulating the proliferation. The normal cells divide only when they receive a particular stimulus. The tumoral cells do not need more this signal.
- Insensitivity to the inhibiting signals
- Abolition of the apoptose or programmed cellular death. In the event of stress or of anomaly not being able to be eliminated, a normal cell commits suicide by using the apoptose. The tumoral cells have inactivated all these mechanisms for better surviving.
- unlimited proliferative Capacity: the usual number of cellular divisions for an human cell is from 50 to 60 (cellular Sénescence, limit of Hayflick ), after which it ceases being able to divide (see article Télomère). The tumoral cells continue to divide unbounded visible thanks to the activity of the télomérase which is strongly active in all the cancer cells.
- Capacity to cause the angiogenèse. The tumoral cells (and the tumor) have an important need oxygenates some to survive. They thus will stimulate the formation of new blood-vessels in order to oxygenate the tumor.
- Acquisition of an invasive capacity. The tumoral cells are able to pass inside a blood-vessel in order to be transported in another body or they will generate one second tumor (metastasis)
Even if there exist elements making it possible to identify a cancer with a great probability, the diagnosis of certainty is not made that on analysis with the Microscope (Anatomopathologie) of a sample of the tumor (possibly helped by other techniques). This sample comes is of a Biopsie (simple taking away of a piece of the tumor) which can be made, according to the localization, following various procedures (Fibroscopie, puncture through the skin…), that is to say of an operational part (tumor removed by the Chirurgie N).
From its initial hearth, cancer goes (apart from any treatment or if the treatment is not effective):
- to develop in a local way. It causes in this case a compression of the close bodies, even an invasion and a destruction of adjacent fabrics;
- to develop in a regional way. It invades the lymphatic ganglia, where the cells of the immune system place;
- to be propagated initial tumor remotely and to form metastasis S. There is often a confusion at the patients and their family: a breast cancer with metastases on the level of the brain does not give a cancer of the brain; it is always the initial breast cancer, but which developed elsewhere. It is necessary to continue to treat it like a breast cancer.
The evolution depends on the type of cancer and its assumption of responsibility: some do only very few metastases and are very sensitive to the treatments making it possible to lead in the large majority of the cases a remission supplements and prolonged (this term of remission is specific cancerology and differs from cure by the absence of certainty as for a repetition with short, average or long run). Others are still controllable with much difficulty and can involve the short-term death. A precise evaluation of the type of cancer near a specialized doctor is thus essential.
Of what does die one when one “dies of a cancer”?
It is there a question frequently put to the doctors by the patients or their family, who have sorrow to believe that small a Tumeur (at least seemingly) threat a whole organization.
The answer is invariable: the life depends on the good walk of a certain number of functions, of which breathing (in the broad sense, by including the distribution of oxygen by blood circulation), digestion and the excretion (Rein S, Foie). According to that of the three systems which is deteriorated by the cancer cells, for example, the patient dies - if one does not manage to suppress the progression of the evil -:
- of respiratory Insufficiency;
- of denutrition;
- of poisoning, by accumulation of toxic substances normally filtered and excreted by the kidneys and the liver.
Principles of treatment
It must be only made in milieu specialized, in rule on a strategy defined by a multi-field medical team (i.e. comprising doctors of several specialities: Oncology, Radiotherapy, surgery, gynecology, gastro-enterology, etc).
- to have a diagnosis certainty and to know the type of cancer;
- to evaluate its local, regional extension and the presence or not of metastasis S;
- to evaluate the general state of the patient (age, functions cardiac and renal, presence of other diseases).
According to the cases, it rests on:
- the exérèse (ablation) surgical broad of the tumor when that is possible, broad wanting to say that the lancet of the surgeon passes only by healthy fabrics;
- a Chemotherapy, regulation of drugs attacking with cancer and its metastases;
- a Radiotherapy, irradiation of the tumor allowing to dissolve, to even disappear, this one.
Certain cancers can also profit:
- of a hormonal treatment;
- of an immunological aiming treatment, which aims at increasing the action of the immunizing system ;
- of a treatment containing Ultrasound S, a technology under development full being based on the focusing of a very powerful ultrasonic beam on a metastasis.
Often, several of these types of treatments are necessary at the same patient.
One should not forget:
- treatment of the consequences of the tumor;
- the assumption of responsibility of the side effects of the treatment;
- the Treatment of the pain.
To learn that one has a cancer is very difficult to assume, so much this new was regarded a long time as that from an imminent Mort. In addition the auxiliary hospitalization, surgical operation and treatments change the life of the patient radically. It is thus essential to bring to the patients an adapted psychological support.
In France, the association of Psycho-oncology studies how to help the cancer patients as well as possible, which passes in general by the participation in groups of patients who live the same tests.
It is based on:
- the avoidance or reduction in the Carcinogenic exposure to the S of the environment and industrialists: mainly, the fight against the Nicotinism, the excessive consumption of alcohol and animal greases, the excessive exposure to the sun, construction standards (asbestos removal), handling of hazardous substances in the professional framework, study REACH;
- the protective role of certain elements: consumption of fibers and antioxydant (cereals, green vegetables, fruits);
- treatment of the précancéreuses lesions .
It is advisable to make the difference between the prevention, which seeks to decrease occurred of the disease while fighting against its supporting factors, and the tracking , which seeks to highlight a disease in an early way to treat it more easily.
See the articles:
It consists of the detection of précancéreuses lesions or cancers at not very advanced stages: one seeks, at a person who does not present symptoms, to highlight the disease in an early way.
That is done by:
- the private clinic (the examination of the patient): palpation of the centres, rectal examination…
- Of the examinations paraclinic: biological radiographies, proportionings.
The goal is to find, in a given population, lesions which one can treat easily: if the symptoms are awaited, it is often necessary to have recourse to heavier treatments to treat the disease.
Trackings having proven their interest (they decrease the number of deaths per cancer) are:
- the Smear of the uterine collar, to detect the précancéreuses lesions and small cancers of the uterine collar
- the Mammography, to detect breast cancers at an early stage
Currently, one seeks to prove the interest of the search for tiny bleedings in the saddles (test Hémocult) for the tracking of the polyps and small cancers of the colon.
Cancer and religion
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