There isn’t a simple, exactly definition of cancer. It comes from Greek word karkinos, what is meaning shell-fish.
In general, the term of cancer is reffering to a group of diseases characterized by unnormal and uncotroled grow of a cell or a group of cells, that invade surrinding tissues and can sprade to distance from the original tissue or organ.
For physician cancer is meaning the evolution of a tumor that distroid localy and remote the healthy tissues or organs of individual affected by disease.
For citologist and pathologist, cancer represents a neoformation tissue that infiltrates healty structures from where it developed.
For biologit it means a change of regulatory systems of growth and diferentiation of normal cells which become dangerous for the rest of the cells.
Cancer is the result of uncontrolled division of cells. We can understand this, seeking the processes that exist in normal cells. Many different tissues build up human body, each of them containing millions of cells. These are disposed in a regular manner, every tissue having its proper cellular structure and architecture. They subject to certain general rules that permit the normal function of the human body.
Constantly, in some tissues, cells are lost due to general wear, being replaced through a process of cellular division. In normal tissues, cellular division and death are controlled through specific mechanisms.
Malignant cells are dividing in an uncontrolled manner, thus their number grows till occurs a tumour clinically visible. On the other hand, malignant cells are enable to organize in an adequate way, and tumoural mass that occur, doesn’t have the characteristics of normal tissue.
Not all tumours are cancerous. Even if some tumours grow in an uncontrolled way, they can be benign or malign. Microscopically, those benign can have the aspect of a normal tissue. They grow and push or displace the surrounding tissues, but don’t invade them. Smaller benign tumours don’t produce symptoms and can be neglected; those bigger are removed after the diagnosis of benign has been established.
Cells of malignant tumour multiply into a normal tissue, invading the surrounding and remote tissues.
These cells spread in the whole body finally, causing the death.
The word “malign” is meaning “bad” comparing with “benign” which means “inoffensive”.
Both describe the occurrence and evolution of two kinds of tumours in lack of treatment.
Cancerous cells develop from normal cells of the body, only one cell being enough for development of a tumour. But of all these, transforming of a normal cell into malign one is gradually, including more steps for a period of many years. Through out these steps the cell is modifying and become less sensitive to normal control mechanisms of the body.
Cancers are classified according to type of stem cell. Those, which develop from epithelial cells, like skin and intestine, are called carcinomas, those which proceed from sustaining structures, such as cartilage, bones and muscles, are called sarcomas.
Carcinomas are more frequent than sarcomas because the epithelial cells are dividing more frequently.
The capacity to spread to distance determines the gravity of this disease. Fortunately, the stage of spreading process are regulated, cancer initially spreading into surrounding tissues. This fact produces local lesions, which in time can determine certain symptoms.
In the next stage, cells start to leave the primary tumor, pass through conjunctive membranes, walls of lymphatic and blood vessels, in lymphatic network. Initially, they’ll invade lymphatic nodes, structures with immune role. First, are invaded the regional nodes, the most closed to tumour. An important number of cells are destroyed here, this representing the loco-regional invasion of cancer. In time, the immune cells of nodes cannot face the influx of malign cells, which continue to multiply.
Farther, the cancerous cells will break this barrier and will arrive through lymphatic stream into bloodstream. Another, modality to enter into bloodstream, is to break the wall of blood vessels at the level of original tumour.
After arriving in bloodstream, cancerous cells will stop in different organs where the local condition, permit the subsequent development: lungs, bones, brain and liver. Here, a part of them will die, but others will survive and will continue to multiply, this representing the stage of metastasis, of generalized disease.
In every stage only the most aggressive and resistant cells will survive, chances of cure or response to treatment decreasing with advancing of disease.
Due to modern medicine peoples have a longer life, this explaining the increasing number of oncological patients.
Of course, some types of cancer are related to lifestyle. Tobacco-related cancer is very rare in countries from the third world. But it is increasing in countries with developed industry where more and more peoples are smoking.
At adults the most frequent forms of cancer affect the lungs, digestive tract and genital organs. Despite of modern medicine, cancer is the second cause of death in most countries including Romania.
At children and adolescents the more frequent forms are: leukemia, lymphomas, renal tumours and brain tumours. Fortunately, these are rare and their treatment has been improved very much in last decades.
The main cause of cancer is still unknown.
Environmental facts, such as chemical pollution and exposure to radiations cause many forms of cancer. Many experiments, that have identified the chemical substances, which cause cancer (carcinogens), have been made on laboratory animals. The most known carcinogen is the smoke from tobacco. Also, the radiations affect the genetic material of a cell – radiations emitted by explosion of atomic bomb in Japan in 1945 have caused many forms of cancer, some of them developing over 10-20 years from exposure to radiations. There are others factors that cause cancer. For example, viruses that affect the genetic structure of cells produce some forms of cancer.
In some cases the immune system is not functioning normally, therefore the cancerous cells cannot be destroyed by it. Researches established that diets rich in fruits and vegetables are able to protect the organism against cancer. It seems that an adequate diet strengthens immune system, which destroys the malignant cells. Certain cancers are due to noxious substances. For example, the tar infiltrated in skin of an animal can cause skin cancer. These chemical substances can affect the genetic structure of a cell transform it in a malignant one.
Cancer is not fatal in all cases. In last decade treatment of cancer has been improved and thousands of peoples are cured annually. However, a cancer less spread is easier to treat than one with a significant spread. Therefore, early diagnosis is vital depending on the presentation to doctor once the first symptoms and signs of disease have occurred.
Diagnosis will be confirmed first. This is done through clinic exam, imagistic and laboratory tests. It is performed a complete examination, paying attention to periphery lymphatic nodes.
A part of the tumor is examined to microscope. This procedure can be done through biopsy or cytology.
Biopsy involves the removal by the surgeon of a part of tumor, which is sent then to pathologist. He’ll seek if the tissue is or not malign. Cytology implies the examination of certain products such as: sputum , mucus from uterine cervix, pleural liquid, aspirated material from tumor, to see if they contain cancerous cells.
Blood tests are done for checking of vital organs.
X-rays films seek the cells spreading in a certain region of the body (lungs, bones, gastrointestinal tract, kidneys).
Isotope scan implies the injection of a small quantity of radioactive substance, which will be trapped more intensive in an organ or area affected by cancer.
The treatment’s goal is to destroy or remove all malign cells from patient’s body. This is possible through correct use of appropriate treatments, usually associated. The treatment is necessary even in advanced stages in order to prolong survival with a better quality of life (palliative treatment).
Surgical methods for cancer’s removal are performed from many years. In some cases surgery has a prophylactic role, removing the pre-cancerous lesions.
In early stages, surgery has a curative role, removing the tumor together with surrounding normal tissues and loco-regional lymphatic nodes.
In advanced stages, surgery integrated in the multidisciplinary complex treatment improves the life’s quality and prolongs the survival.
Uses ionizing radiation to destroy cancerous cells, which are enable to divide continuously. Unfortunately, it destroys the normal cells, too.
Certain forms of cancer can be cured through radiotherapy, without surgical operation. In order to improve the outcome of the treatment, in some cases, radiotherapy can be delivered pre or post surgery.
Radiotherapy is an efficient method of symptomatic treatment (pain, bleeding, pushing) with purpose to improve life’s quality.
Modern machines enable administration of efficient doses of radiation targeted on tumour, with minimal side effects for normal tissues. In some cases is performed the implantation of radioactive substances in area affected by cancer. This provide a greater dose to the tumour, only a small dose being delivered normal surrounding tissues. This treatment method is ideally, because the alteration of normal tissue is minimal.
Treatment last only few minutes, is not painful and is delivered daily, five days a week, during some weeks, depending on dose; it doesn’t require patient’s hospitalization. It is very important that the patient to preserve the same position every day of the treatment.
There are tumours very sensitive to chemotherapics and they can be cured even in advanced stages. In most cases chemotherapy is associated to other treatment modalities, in order to improve the local and to distance control of the disease.
It is used in monotherapy (one drug) or polichemotherapy (association of two or more drugs). Treatment is delivered in series, which are repeated to every 3-4 weeks. It is delivered only under the control of specialist.
Chemotherapics drugs are aggressive substances, that destroy the malignant cells, and sometimes they can affect the normal cells, in this way occurring the side effects. This is the main inconvenient of chemotherapy, but in most of cases these are reversible and can be managed through symptomatic drugs.
Chemotherapy is probably the most dynamic segment of the treatment. Permanently, there are studied new drug associations, new drugs, new protectors and modulators.
Some tumours are hormone-depended and hormonal drugs constitute an efficient treatment associated with the others modalities, mentionated above. It is used specially in breast cancer, prostate cancer and uterine cervix cancer.
Nonspecific Immunotherapy (interferone, interleukine, BCG) and specific Immunotherapy (monoclonal antibody, antitumoral vaccines).
Gene therapy-treatment which correct the genetic abnormality that caused the disease; being ethiologic it represent the most promising treatment of the future.
In case that there are more efficient treatments for cancer these are associated in an planed sequence of treatment.
In oncology the treatment is individualized for each patient. Treatment plan is set up by a multidisciplinary commission of treatment, made up by a surgeon, a radiotherapist, an oncologist and a pathologist.