While the target of antineoplastic agents is the cancer cell, these agents are unable to distinguish between normal and cancer cells. Some temporary damage will occur to normal cells, especially those cells that are rapidly dividing, such as bone marrow, gonads, gastrointestinal mucosa and hair follicles.
Some drugs have an affinity to certain organs in the body (e.g. bleomycin and lung tissue), and toxicity may occur in these organs over time.
Responses to antineoplastic therapy can be classified as: