Browse by author
Lookup NU author(s): Professor James WasonORCiD
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License (CC BY-NC 4.0).
© SAGE Publications. Traditionally, phase II cancer trials test a binary endpoint formed from a dichotomisation of the continuous change in tumour size. Directly testing the continuous endpoint provides considerable gains in power, although also results in several statistical issues. One such issue is when complete responses, i.e. complete tumour removal, are observed in multiple patients; this is a problem when normality is assumed. Using simulated data and a recently published phase II trial, we investigate how the choice of test affects the operating characteristics of the trial. We propose using parametric tests based on the censored normal distribution, comparing them to the t-test and Wilcoxon non-parametric test. The censored normal distribution fits the real dataset well, but simulations indicate its type-I error rate is inflated, and its power is only slightly higher than the t-test. The Wilcoxon test has deflated type I error. For two-arm designs, the differences are much smaller. We conclude that the t-test is suitable for use when complete responses are present, although positively skewed data can result in the non-parametric test having higher power.
Author(s): Wason JMS, Mander AP
Publication type: Article
Publication status: Published
Journal: Statistical Methods in Medical Research
Year: 2015
Volume: 24
Issue: 6
Pages: 909-919
Print publication date: 01/12/2015
Online publication date: 16/12/2011
Acceptance date: 01/01/1900
Date deposited: 26/01/2018
ISSN (print): 0962-2802
ISSN (electronic): 1477-0334
Publisher: SAGE Publications Ltd
URL: https://doi.org/10.1177/0962280211432192
DOI: 10.1177/0962280211432192
PubMed id: 22179821
Altmetrics provided by Altmetric
