Cancer

ChemotherapyThe term chemotherapy refers to treatment of disease by chemicals that affect cell function. Popularly, the term refers to antineoplastic chemotherapy, a treatment for cancer which are used anticancer drugs. In diabetes (specifically Type 1 diabetes) is an accomplished treatment that included high-dose chemotherapy and stem cell transplantation own (from their own bone marrow) that can cure the disease detected in the early months.
Chemotherapeutic agents can also be used to treat autoimmune diseases such as multiple sclerosis and rheumatoid arthritis. Can be used also for suppression of transplant rejections various (immunosuppression).
HistoryThe use of chemicals and drugs such as medication date at the time of Persian physician, Muhammad ibn Zakariya Razi (or Rasis), which in the tenth century introduced the use of chemicals such as sulfuric acid, copper, mercury and arsenic salts, sal ammoniac, gold, chalk, clay, coral, pearl, tar, bitumen and alcohol for medical purposes.
The first drug used for cancer chemotherapy, however, dates back to the twentieth century, through a substance that was not primarily used for this purpose. The mustard gas was used in chemical warfare during the First World War and was subsequently studied during the Second World War. During a military operation in World War II, a group of people were accidentally exposed to mustard gas and later discovered that she had a decrease in the count of blood leukocytes. It was reasoned that an agent that damaged the rapidly growing white blood cells should have a similar effect on cancer. After that, in the 40s, many patients with advanced lymphoma received the drug intravenously, instead of inhaling the gas. Their improvement, although temporary, was remarkable. This experience led the research with other substances that have similar effects against cancer. As a result, many other drugs have been developed to treat cancer.
PrincipleCancer is an uncontrolled growth of cells that invade a tissue, get around or do the metastasis and destroy, both locally and remotely, other healthy tissues of the body. In other words, cancer is the term that is used to define a group of diseases with one common denominator: the transformation of normal cell into one that behaves very dangerous to the human body. It also uses the word cancer but this, like definçãotumor can mean a variety of benign.
Many chemotherapy drugs work impairing cellular mitosis (see also cell division), in effect, affecting the fast-growing cells. As these drugs cause cell damage, they are called cytotoxic or citotásticas. Some of these drugs lead to cell apoptosis (also called programmed cell death). This means that other rapid cell division as those responsible for hair growth and replacement of the epithelium of the gut wall are also affected. However, some drugs have fewer side effects than others, allowing the physician to adjust treatment, bringing benefits to patients.
Because chemotherapy affects cell division, tumors with high growth (such as acute myeloid leukemia and aggressive lymphomas, including Hodgkin's lymphoma, are more sensitive to this treatment because they present a large proportion of target cells undergoing cell division. Since the tumors with low growth, such as indolent lymphomas, have a tendency to respond more modestly to chemotherapy.
Tumor drugs affect "younger" (more differentiated) more effectively, because the mechanisms that regulate cell growth are preserved. With the subsequent generation of tumor cell, differentiation is lost, the growth becomes less regulated, and tumors become less responsive to most chemotherapeutic agents. Near the center of solid tumors, cell division stops, making them insensitive to chemotherapy. Another problem with solid tumors is the fact that chemotherapy agents generally do not reach the core, ie, the center of the tumor. Solutions to these problems include radiation therapy and surgery.
Over time, the cancer cells become more resistant to chemotherapy treatment. Recently, scientists have identified small bombs in the area of the surface of cancer cells that actively move chemotherapy from the cell out. Research with the P-glycoprotein pumps and other effluents from chemotherapy are underway, as well as drugs that inhibit the function of P-glycoprotein, which are being tested since June 2007.
Types of chemotherapy    * Multidrug therapy: is the association of various cytotoxics that act with different mechanisms of action, synergistically, in order to decrease the dose of each drug individually and increase the therapeutic potency of all the substances together. This combination chemotherapy is usually defined according to type of drug that form the association, dose and administration time, forming a scheme of chemotherapy.    * Adjuvant chemotherapy: is chemotherapy that is administered usually once a main treatment, such as surgery to reduce the incidence of distant dissemination of cancer.    * Neoadjuvant or induction chemotherapy: Is chemotherapy that starts before any surgery or radiotherapy, in order to evaluate the effectiveness of treatment in vivo. Neoadjuvant chemotherapy reduces the tumor status and may improve the outcome of surgery and radiotherapy and in some cases, the response to reach the surgery is a prognostic factor.    * Concomitant radiochemotherapy: Also called chemoradiation, is usually administered in conjunction with radiotherapy, in order to potencilizar the effects of radiation or work specifically with it, optimizing the local effect of radiation.