Investigation of relationship between change in locoregional control and change in overall survival in randomized controlled trials of modified radiotherapy in head-and-neck cancer.

Abstract

To establish whether a relationship exists between improvement in locoregional control (LRC) and improvement in overall survival (OS) in trials of modified radiotherapy for head-and-neck cancer and to attempt to quantify the relationship. A systematic review of the literature was performed for randomized controlled trials of radiotherapy for head-and-neck cancer involving the use of altered fractionation or hypoxic sensitizers. The changes in LRC at 2 years and OS at 5 years were recorded for each trial. Regression analysis was used to investigate the relationship between the two variables. Nineteen relevant trials were identified. Fourteen reported sufficient data for analysis. Linear regression analysis showed a statistically significant correlation between LRC and OS with a slope of 0.67 (95% confidence interval, 0.38-0.96, p = 0.00017). We have demonstrated a relationship between a change in LRC and a change in OS in randomized trials of modified radiotherapy for head-and-neck cancer. A 10% improvement in the 2-year LRC is predicted to lead to a 6.7% improvement in the 5-year OS. This type of analysis may have applications in other tumor sites.