of the cancer-killing agents. Now, with greater understanding of the nature of cancer and of how chemicals interact, chemotherapy has become a standard therapy. Either alone or in combination with other treatments, chemotherapy can now cure some common forms of cancer—testis cancer, leukemia, choriocarcinoma , many cases of Hodgkin's disease and non-Hodgkin's lymphomas and some cases of ovarian cancer.

The Range of Drugs  For many years, researchers looked hard for one single drug—a "magic bullet"—that would cure cancer. This has yet to be found, if it exists at all. Today, about 50 anticancer drugs are available on the market. About a dozen others have not yet been approved for general distribution but have proved to be useful in some forms of cancer. These experimental or investigational drugs are supplied to clinical trial investigators under a special government license.
    To make drugs available earlier for therapy, some drugs with an established role in treatment are also made available to practicing oncologists even though they are not yet on the retail market. In 1989, for example, the drug levamisole was made available to be used in combination with 5-fluorouracil for treatment of Dukes' Stage C carcinoma of the colon. This new policy may mean earlier release of new drugs in the future.