Clinical trial methods to discover and validate predictive markers for treatment response in cancer.

Although postoperative chemotherapy in the treatment of cancer appears to have reached the limit of cytoreduction, this may be due to chemotherapeutic agents that are administered nonselectively rather than attainment of the true limit of cytoreduction. Molecular profiles of tumor cells may determine tumor response to chemotherapy, and therefore the selective use of chemotherapy based on prediction will ultimately provide a cure for breast cancer. In this paper, design strategies for clinical trials aimed at disclosing predictive markers are discussed.