Maximum of the weighted Kaplan-Meier tests with application to cancer prevention and screening trials

A class of maximum weighted Kaplan-Meier test statistics is described where the weight functions are chosen from a family of smooth functions. The inv estigated test statistic is robust and sensitive to a variety of alternativ es that are often observed in cancer prevention and screening trials. A sim ulation study is performed to compare the size and power properties between the proposed test statistics and some existing ones. We illustrate the pro cedure using data from a clinical trial of a breast cancer screening progra m.