How Does Chemotherapy Work
Most chemotherapy drugs work by stopping rapidly dividing cells from multiplying. The drugs do this by interrupting the cells ability to create DNA during division. Without DNA formation, the cells are not viable. Chemotherapy drugs only work against cells that are newly forming. Cells that are in a resting stage and not dividing, are not affected. Basically, chemotherapy does not technically kill cells, it stops new cells from correctly forming.
Because chemotherapy only affects dividing cells, leaving resting cells unaffected, multiple chemotherapy treatment sessions are required. The idea is that continuing chemotherapy treatments will catch previous resting cells during the division stage.
There are over 100 types of chemotherapy drugs. Some affect different cells than others and some interrupt cell division in different ways. Doctors sometimes administer multiple types of chemotherapy drugs to a patient in an attempt to better attack cancer cells.
Side-effects from chemotherapy occur because chemotherapy does not differentiate between normal cells and cancer cells. Normal rapidly dividing cells are affected as well. Examples of rapidly dividing cells are hair follicles, cells that line the inside of the mouth and cells that line the inside of the intestines, are affected. This is why chemotherapy treatment can cause side-effects of hair loss, mouth ulcers and intestinal upset.
How chemotherapy is administered and how often depends on the type of cancer and its severity. Chemotherapy is usually administered intravenously, but it is sometimes given through an injection or orally. Treatments may be administered daily, weekly or monthly. Usually, chemotherapy is given in treatment cycles, allowing for breaks between treatment to allow normal cells in the body to recover. For example, chemotherapy may be given once a day for three weeks, with a two week break, followed by another three weeks of treatment.