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AGENCY USE ONLY (Leave blank) 2. REPORT DATEOctober 1999
REPORT TYPE AND DATES COVERED
Final (30 Sep 94 -29 Sep 99)
TITLE AND SUBTITLE
Statistical Methods for Analyzing Time-Dependent Events in Breast Cancer Chemoprevention Studies
AUTHOR(S)George Wong, Ph.D.
FUNDING NUMBERS
DAMD17-94-J-4332
PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES)Strane Cancer Prevention Center New York, New York 10021 e-mail: gwong@strang. org
PERFORMING ORGANIZATION REPORT NUMBER
SPONSORING / MONITORING AGENCY NAME(S) AND ADDRESS(ES)U
12a. DISTRIBUTION / AVAILABILITY STATEMENTApproved for public release distribution unlimited
12b. DISTRIBUTION CODE■IO «peTP«/~r /.*-: __-... . , The overall aim of our research proposal is the statistical non-
ABSTRACT (Maximum 200 Words) iparametric inferences of the redistribution-to-the-center estimator (RTCE) and the generalized maximum likelihood estimator (GMLE) for the survival function of a time-to-event variable that is subject to interval censoring. The RTCE, which is proposed by us, has a closed-form expression and is equal to GMLE under a homogeneous condition. The GMLE is the standard estimator in survival analysis. However, it cannot be expressed in a closedform expression, and asymptotic distribution theory for it has been limited. Prom the study of the asymptotic properties of RTCE, we have gained important insight into proofs of asymptotic properties of GMLE. Specifically, we have established consistency, asymptotic normality and efficiency of GMLE under different conditions. Also, we have derived an asymptotic nonparametric two-sample distance test for comparing two populations. Under finite distributional assumptions on the survival and censoring distributions, we have established consistency, asymptotic normality for both the regression coefficients and the survival function of the Cox regression model. We point out major computational limitations associated with the Newton-Raphson algorithm for computing the asymptotic estimates of the .Cox regression parameters, and suggest a simpler two-step estimation alternative
SUBJECT TERMSBreast Cancer, Interval-Censored Data, Consistency, Asymptotic Normality, Cox Regression Where copyrighted material is quoted, permission has been obtained to use such material.Where material from documents designated for limited distribution is quoted, permission has been obtained to use the material.Citations o...