From a historical view, we learned that the Egyptians were the first to use chemotherapy, and that serious investigation of chemotherapy started with the observation of some unusual reactions of soldiers exposed to some chemicals used in World War II.
We learned that all cells, healthy and malignant, go through distinct phases in their life cycle. This is called the cell cycle. Chemotherapy drugs are designed to disrupt a cell's function at one or all of these phases. It is also important to know that normal cells, as well as cancer cells, are affected by chemotherapy, and the cause of unpleasant side effects is toxicity of the drugs to normal cells.
Chemotherapy can be used for curative and palliative purposes and it is often given after other therapies (such as surgery or radiation) have destroyed the clinically detectable cancer cells (adjuvant chemotherapy).
In the discussion of chemotherapy drugs, we learned that there are different ways that chemotherapeutic agents are administered: oral chemotherapy; intravenous chemotherapy; and intrathecal chemotherapy.