The risk of malignancy with normal aging may be a result of cumulative cellular mutations (10). The interaction of the normal aging process and exposure to mutagenic cytotoxic therapies may result in an increased risk of second malignancy, particularly after radiotherapy and treatment with alkylating agents and podophyllotoxins. Commonly cited second cancers
include leukemia after alkylating agents and podophyllotoxins (55,56); solid tumors, including breast, bone and thyroid cancer in radiation fields (57); and bladder cancer after cyclophosphamide. Second cancers may also occur in the same organ site (e.g., breast, colorectal); thus there is definite need for continued surveillance (4,10,11).