 As a working hypothesis, investigators suspect that the transformation from an androgen-dependent to an androgen-independent phenotype is mediated by expansion of an androgen-independent clone already present at the time of ADT that continues to grow while androgen-sensitive clones are being suppressed. It is thus desirable to bring treatment to bear on the androgen-independent component while the corresponding tumor burden remains minimal and prolong the time to hormone resistance. Investigators view the androgen-independent component as analogous to microscopic residual or micro-metastatic disease, for which adjuvant chemotherapy has been shown to be effective in other contexts, even when the same drugs had little or no impact on survival in the setting of more advanced disease. 