Med . 1999; 18: 695- 706. Prentice RL, Kalbfleisch JD, Peterson A, Flournoy N, Farewell V, Breslow N. “The analysis of failure times in the presence of competing risks”. Biometrics 1978; 34: 541-554. Shih JH. “Sample size calculation for complex clinical trials with survival endpoints.” Controlled Clinical Trials 1995; 16:395-407. S tein WD, Gulley JL, Schlom J, Madan RA, Dahut W, Figg WD, Ning Y, Arlen PM, Price D, Bates SE, Fojo T. “Tumor Regression and Growth Rates Determined in Five Intramural NCI Prostate Cancer Trials: The Growth Rate Constant as an Indicator of Therapeutic Efficacy”. Clin.