Biomaterial Database

Interim analyses of survival data in cancer clinical trials. 1998

E Skovlund

Norwegian Cancer Society and Section of Medical Statistics, University of Oslo. eva.skovlund@klinmed.uio.no

It is common practice to undertake interim analyses of accumulating survival data in a cancer clinical trial while patient entry and/or follow-up is still in progress. The purpose of making an interim analysis is to stop the trial if a convincing treatment difference can be demonstrated. The main problem with repeated significance tests is that the more often one analyses accumulating data, the greater the probability of eventually obtaining a significant result, p < 0.05 say, even when there is in reality no treatment difference. To allow for repeated testing one must therefore choose a more stringent nominal significance level as a criterion for stopping the trial. Repeated significance tests are normally applied at equally spaced intervals, and the maximum number of tests is decided in advance. This paper presents and compares the properties of two simple and commonly applied strategies for undertaking interim analyses of accumulating survival data.

UI	MeSH Term	Description	Entries
D009369	Neoplasms	New abnormal growth of tissue. Malignant neoplasms show a greater degree of anaplasia and have the properties of invasion and metastasis, compared to benign neoplasms.	Benign Neoplasm,Cancer,Malignant Neoplasm,Tumor,Tumors,Benign Neoplasms,Malignancy,Malignant Neoplasms,Neoplasia,Neoplasm,Neoplasms, Benign,Cancers,Malignancies,Neoplasias,Neoplasm, Benign,Neoplasm, Malignant,Neoplasms, Malignant
D002986	Clinical Trials as Topic	Works about pre-planned studies of the safety, efficacy, or optimum dosage schedule (if appropriate) of one or more diagnostic, therapeutic, or prophylactic drugs, devices, or techniques selected according to predetermined criteria of eligibility and observed for predefined evidence of favorable and unfavorable effects. This concept includes clinical trials conducted both in the U.S. and in other countries.	Clinical Trial as Topic
D003198	Computer Simulation	Computer-based representation of physical systems and phenomena such as chemical processes.	Computational Modeling,Computational Modelling,Computer Models,In silico Modeling,In silico Models,In silico Simulation,Models, Computer,Computerized Models,Computer Model,Computer Simulations,Computerized Model,In silico Model,Model, Computer,Model, Computerized,Model, In silico,Modeling, Computational,Modeling, In silico,Modelling, Computational,Simulation, Computer,Simulation, In silico,Simulations, Computer
D005500	Follow-Up Studies	Studies in which individuals or populations are followed to assess the outcome of exposures, procedures, or effects of a characteristic, e.g., occurrence of disease.	Followup Studies,Follow Up Studies,Follow-Up Study,Followup Study,Studies, Follow-Up,Studies, Followup,Study, Follow-Up,Study, Followup
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D013223	Statistics as Topic	Works about the science and art of collecting, summarizing, and analyzing data that are subject to random variation.	Area Analysis,Estimation Technics,Estimation Techniques,Indirect Estimation Technics,Indirect Estimation Techniques,Multiple Classification Analysis,Service Statistics,Statistical Study,Statistics, Service,Tables and Charts as Topic,Analyses, Area,Analyses, Multiple Classification,Area Analyses,Classification Analyses, Multiple,Classification Analysis, Multiple,Estimation Technic, Indirect,Estimation Technics, Indirect,Estimation Technique,Estimation Technique, Indirect,Estimation Techniques, Indirect,Indirect Estimation Technic,Indirect Estimation Technique,Multiple Classification Analyses,Statistical Studies,Studies, Statistical,Study, Statistical,Technic, Indirect Estimation,Technics, Estimation,Technics, Indirect Estimation,Technique, Estimation,Technique, Indirect Estimation,Techniques, Estimation,Techniques, Indirect Estimation
D013269	Stochastic Processes	Processes that incorporate some element of randomness, used particularly to refer to a time series of random variables.	Process, Stochastic,Stochastic Process,Processes, Stochastic
D016019	Survival Analysis	A class of statistical procedures for estimating the survival function (function of time, starting with a population 100% well at a given time and providing the percentage of the population still well at later times). The survival analysis is then used for making inferences about the effects of treatments, prognostic factors, exposures, and other covariates on the function.	Analysis, Survival,Analyses, Survival,Survival Analyses
D018401	Sample Size	The number of units (persons, animals, patients, specified circumstances, etc.) in a population to be studied. The sample size should be big enough to have a high likelihood of detecting a true difference between two groups. (From Wassertheil-Smoller, Biostatistics and Epidemiology, 1990, p95)	Sample Sizes,Size, Sample,Sizes, Sample
D018579	Patient Selection	Criteria and standards used for the determination of the appropriateness of the inclusion of patients with specific conditions in proposed treatment plans and the criteria used for the inclusion of subjects in various clinical trials and other research protocols.	Patient Recruitment,Research Subject Recruitment,Selection Criteria,Research Subject Selection,Selection for Treatment,Selection of Research Volunteers,Selection of Subjects,Criteria, Selection,Recruitment, Patient,Recruitment, Research Subject,Recruitments, Research Subject,Research Subject Recruitments,Research Subject Selections,Research Volunteers Selection,Research Volunteers Selections,Selection for Treatments,Selection, Patient,Selection, Research Subject,Selections, Research Subject,Subject Recruitment, Research,Subject Recruitments, Research,Subject Selection, Research,Subject Selections, Research,Subjects Selection,Subjects Selections,Treatment, Selection for,Treatments, Selection for,Volunteers Selection, Research