ABSTRACT
The aggressive treatment of human tumors involving ionizing radiation and chemotherapeutic agents has produced long-term survivors of certain types of cancer. Because almost all chemotherapeutic agents and ionizing radiation are known to be mutagenic and carcinogenic, the possibility of developing secondary neoplasms among long-term survivors of cancer is not an unexpected observation. Indeed, an increasing number of secondary malignancies with shorter latent periods is being reported, especially among children. There are instances where either ionizing radiation or chemotherapeutic agents alone have induced secondary malignancy; however, in most instances, the appearance of a second malignancy among long-term survivors of cancer is the result of the net effect of both ionizing radiation and chemotherapeutic agents. Experimental data using tissue culture have already suggested that the combined treatment of hamster embryo cells with ionizing radiation and benzo[a]pyrene dramatically enhances (nine-fold) the frequency of transformation. Therefore, the increased incidence of secondary malignancy among long-term survivors of cancer treatment is not surprising. In addition to malignancy, there are other non-neoplastic changes that are being observed in an increasing number. The purpose of this chapter is to describe the most recent information on the long-term consequences of current tumor treatment modalities.
