November 10, 2008
Cancer chemotherapy consist of Cytotoxic drugs, hormones, antihormones, and biologic agents have become increasingly effective means of treating cancer. Many patients are treated on protocols to provide optimal therapy for refractory or poorly responsive malignancies. Treatment may be inadequate or ineffective because of drug resistance of the tumor cells. This has been attributed to spontaneous genetic mutations in subpopulations of cancer cells prior to exposure to chemotherapy. After chemotherapy has eliminated the sensitive cells, the resistant subpopulation grows to become the predominant cell type (Goldie-Coldman hypothesis). This has been the basis of alternating non-cross-resistant chemotherapy regimens.
