A quality-adjusted reanalysis of a Phase III trial comparing once-daily thoracic radiation vs. twice-daily thoracic radiation in patients with limited-stage small-cell lung cancer(1).

Abstract

We undertook an analysis of quality-adjusted survival using the Q-TWiST (Quality Time Without Symptoms or Toxicity) methodology and developed a new graphic representation called a quality-adjusted life-years plot, which presents a complete and concise Q-TWiST analysis on a single plot. The Q-TWiST plot incorporates the time without symptoms or toxicity and several combinations of utility coefficients for toxicity and relapse days into the same plot. In addition, the plot includes threshold lines, to judge whether a particular combination of utility coefficients reaches a significance level. The differential in toxicity incidence and severity between the two thoracic radiation treatment arms was inconsequential. Sensitivity analyses were run using Q-TWiST plots. For all combinations of the various toxicity definitions and utility coefficients, the median Q-TWiST was greater for the once-daily thoracic radiation treatment arm than for the twice-daily treatment arm, without achieved significance. This work refines the results previously reported for this Phase III clinical trial in patients with limited-stage small-cell cancer, and there was no significant difference in survival after adjusting for toxicity and progression. Furthermore, the new methods developed for this trial allow for a more detailed and parsimonious presentation of survival and toxicity data for all oncology clinical trials.