Long-term survival with non-proportional hazards: results from the Dutch Gastric Cancer Trial
Article first published online: 30 AUG 2005
Copyright © 2005 John Wiley & Sons, Ltd.
Statistics in Medicine
Volume 24, Issue 18, pages 2807–2821, 30 September 2005
How to Cite
Putter, H., Sasako, M., Hartgrink, H. H., van de Velde, C. J. H. and van Houwelingen, J. C. (2005), Long-term survival with non-proportional hazards: results from the Dutch Gastric Cancer Trial. Statist. Med., 24: 2807–2821. doi: 10.1002/sim.2143
- Issue published online: 30 AUG 2005
- Article first published online: 30 AUG 2005
- Manuscript Accepted: 9 DEC 2004
- Manuscript Received: 3 JUN 2004
- long-term survival;
- non-proportional hazards;
- time-dependent covariate effects
Randomized clinical trials with long-term survival data comparing two treatments often show Kaplan–Meier plots with crossing survival curves. Such behaviour implies a violation of the proportional hazards assumption for treatment. The Cox proportional hazards regression model with treatment as a fixed effect can therefore not be used to assess the influence of treatment of survival. In this paper we analyse long-term follow-up data from the Dutch Gastric Cancer Trial, a randomized study comparing limited (D1) lymph node dissection with extended (D2) lymph node dissection. We illustrate a number of ways of dealing with survival data that do not obey the proportional hazards assumption, each of which can be easily implemented in standard statistical packages. Copyright © 2005 John Wiley & Sons, Ltd.