Chemotherapy is using chemicals to get rid of cancer
cells. Please note this is general information. Each malignancy is different. Every patient is an individual. Please talk to your treatment team. The sources used here know their information. The physicians know you. These chemicals are known as anti cancer drugs. A synonym is cytotoxic drugs. Cytotoxic means toxic to cells. The purpose of chemotherapy is to kill off the cancer. If that is not possible to prolong life as much as possible. To relieve symptoms and make the patient comfortable.
The first chemotherapy drug was mustard gas. It was used in WW1 for warfare and discovered in medical studies in WW2 to be an effective chemotherapy substance.
Basically chemotherapy agents are used in the destruction of cancer cells. How they do this depends on the type of anticancer drug. The goal is the same. Preventing cancer cells from reproducing. The difference is the method used. Each cancer patient is individualized for chemotherapy therapy by the cancer and the person.
There are different types of anticancer medicines. The categories are alkylating agents, antimetabolites, antitumor antibiotics, Topoisomerase inhibitors, mitotic inhibitors, corticosteroids, platinum drugs, vitamins.
Alkylating agents work by directly damaging the DNA of the cell. The DNA is the genetic code that enables the cell to reproduce itself. If the DNA is ruined there is no cell reproduction. Ergo the cancer can't spread. They can be effective in what ever phase cycle the cell is in. The problem is long term damage to the bone marrow can result. Even in some cases, can lead to acute leukemia. The smaller the dosage , the less chance this will happen.
Some examples are nitrogen mustard, alkyl sulfonates, triazines and ethylenamines.
Platinum drugs are similar in methodology to alkylating agents. They are much less likely to cause leukemias. Sometimes they're used in conjunction with alkylating agent
Antimetabolites are either purine or pyrimidine inhibiting drugs. They basically prevent certain building blocks of DNA. They block normal development, division of cancer cells
Examples are Mycophenolate, 5 flourouracil aka 5FU, Methotrexate. aka is short for also known as.
Cancer antibiotics are mostly in the anthracycline class. They block enzymes dealing with DNA replication. They are effective in every cell cycle phase. Examples are the anticarcinogen drugs ending in rubicin. Examples Idarubicin, daunorubicin, doxirubicin.
Topoisomerase inhibitors inhibit an enzyme called topoisomerase. This makes it difficult for the cell to copy its DNA to produce other cancer cells.
Mitotic inhibitors can be derived from herbal sources. They can prevent mitosis. That is they can stop enzymes fr om producing proteins to make new cells.
Some examples are taxol, vinblastine, vincristine. Taxol is from Yew and the latter two are from Periwinkle.
Corticosteroids are hormones, specifcially steroids used to fight certain hormone related cancers. There are other uses for these drugs, unrelated to cancer fighting.
There is a form of vitamin A used for a certain subtype of acute myeloid leukemia called acute promylocytic leukemia. It is known as AML subtype M3. This is from the French American British classification system of 7 AML subtypes.
The WHO (World Health Organization classifications differ.
What chemotherapy is used depends on the type of cancer, the staging, what your body can tolerate and goal of the treatment. Treatment should be geared toward each patient.
What is cancer? Cancer starts with only one cell that begins to divide rapidly to the point of being capable of either forming a tumor and/or destroying other normal cells.
The controversy and major issue with chemotherapy is not only are the cancer cells killed off, but so are normal ones. This is the main reason there are antichemotherapy sites on the net and in print. When they state chemo-medications are destructive to normal cells, this is a truthful statement. Yet equally true chemotherapy at least for now is the most effective method to fight cancer.
The reason non malignant cells are attacked is its virtually impossible for the chemo to distinguish between cancerous and non cancerous cells. Chemo agents tend to destroy fast growing cells. Most cancer cells are fast growing. Unfortunately so are hair cells. Cells lining the digestive tract tend to grow rapidly too.
I predict X number of years, we'll look back and wonder how such a primitive methodology was used. Fortunately medical researchers are looking into more targeted therapies. One of these are monoclonal antibodies. They are geared to target the cancer cells and leave other cells alone.
Common side effects are losing one's hair and nausa and vomiting. As for the former side effect sometimes not only the head hair but body hair is lost as well. This is known as complete alopecia. Fortunately it is usually temporary. Some people are quite upset at losing their hair. For these persons there are wigs. Others take it in stride and their attitude is bald is beautiful. There is no right or wrong here.
Nausea and vomiting can be treated through antiemetic drugs. Emetic means induces vomiting. For most side effects there are drugs of varying effectiveness. This includes mouth sores, constipation, diarrhea. Low red blood cells and platelets can be treated by transfusions. The only way to treat low white blood cells is by colony st imulating factor medicines such as Neupogen, filgrastim.
There are precautions too. Chemo can result in low white blood cells, low red blood cells and low platelets. For low white blood cells, precautions are used. Everyone seeing the patient may need to wear a hospital gown, gloves and if needed a surgical mask to prevent infections. Medical instruments may need to be sterilized. Low red blood cells induces anemia. Best for this is rest. Low platelets means bleeds easily. Nothing sharp in any body cavity, no hand razors, no teeth flossing either. The medical term for low platelets is thrombocytopenia. Low white cells is either leukocytopenia or neutropenia.
Chemotherapy is sometimes given through a vein. This is done usually through a catheter. A catheter is a thin tube that is quite flexible. Some persons have catheters inserted outpatient so there can be a flexible chemo schedule. One end of this device is inserted in a large vein in the chest. The other end either goes in to a minute implant subdermal. Or it is attached outside the body. Chemotherapy can be done by injection into the muscle. The chemo is then released through the bloodstream. Lastly some chemo meds can be given by mouth either by pills, capsules, caplets etc. How it is taken depends on the chemotherapeutic agent, the person and the type of cancer. What ever method is used, the task is the same. The goal of chemotherapy is to kill cancer.
The benefit of chemotherapy is that it can treat cancer that's spread beyond the point where it originated. In other words it can treat for example a lung cancer that metastasized to the brain. It can treat any cancer that traveled anywhere beyond the point of origin. This is not true with surgery and radiation. They too, however have their uses in treating cancer too. No treatment is right for everyone. The oncologists and perhaps other physicians need to decide what are the most effective options.
Sources, www.medicine.net. www.webmd.com, cancer.gov, Nat. Cancer Inst.),cancer.org (American Cancer Society), www.chemomd.com, livestrong.org ( Lance Armstrong Live Strong Program)
