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Using continuous data on tumour measurements to improve inference in phase II cancer studies

Lookup NU author(s): Professor James WasonORCiD



This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).


In phase II cancer trials, tumour response is either the primary or an important secondary endpoint. Tumour response is a binary composite endpoint determined, according to the Response Evaluation Criteria in Solid Tumors, by (1) whether the percentage change in tumour size is greater than a prescribed threshold and (2) (binary) criteria such as whether a patient develops new lesions. Further binary criteria, such as death or serious toxicity, may be added to these criteria. The probability of tumour response (i.e. 'success' on the composite endpoint) would usually be estimated simply as the proportion of successes among patients. This approach uses the tumour size variable only through a discretised form, namely whether or not it is above the threshold. In this article, we propose a method that also estimates the probability of success but that gains precision by using the information on the undiscretised (i.e. continuous) tumour size variable. This approach can also be used to increase the power to detect a difference between the probabilities of success under two different treatments in a comparative trial. We demonstrate these increases in precision and power using simulated data. We also apply the method to real data from a phase II cancer trial and show that it results in a considerably narrower confidence interval for the probability of tumour response.© 2013 The authors. Statistics in Medicine published by John Wiley & Sons, Ltd.

Publication metadata

Author(s): Wason JMS, Seaman SR

Publication type: Article

Publication status: Published

Journal: Statistics in Medicine

Year: 2013

Volume: 32

Issue: 26

Pages: 4639-4650

Print publication date: 20/11/2013

Online publication date: 18/06/2013

Date deposited: 31/01/2018

ISSN (print): 0277-6715

ISSN (electronic): 1097-0258

Publisher: John Wiley & Sons Ltd


DOI: 10.1002/sim.5867

PubMed id: 23776143


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