Presentation (CTI)

OBJECTIVES: Quality-Adjusted Time Without Symptoms or Toxicity (Q-TWiST) is an approach that integrates patients' quality of life and safety into the assessment of survival through three health states: toxicity (TOX), time without symptoms and toxicity (TWiST), and progression (PROG). By assigning utility weights to health state durations, Q-TWiST produces a single metric that evaluates clinical benefits and risks of treatments evaluated. This study aims to highlight the advantages of extrapolating Q-TWiST for long-term survival estimates compared to using observed clinical trial data, where health state durations may be incomplete.
METHODS: Both observed and extrapolated Q-TWiST were used to assess differences in quality-adjusted survival between treatment arms. Health state utility values were derived from EQ-5D-5L to measure quality of life. Survival data were extrapolated over a lifetime horizon using the Weibull distribution, allowing for long-term projections beyond the clinical trial follow-up period.
RESULTS: Extrapolated Q-TWiST showed significant improvements in quality-adjusted survival for the intervention arm compared to the control arm. This extrapolated approach ensures a more comprehensive evaluation, capturing treatment benefits that may be missed when limiting analyses to observed trial data. Extrapolated Q-TWiST can also be viewed as analogous to traditional Quality-Adjusted Life Years (QALY) in partitioned survival models when extrapolated over a lifetime horizon.
CONCLUSIONS: Extrapolating Q-TWiST offers a valuable approach to evaluate quality-adjusted survival and toxicity in oncology. By providing insights that complement traditional QALY analyses, this method supports informed decision-making in oncology, emphasizing its potential as a valuable tool for clinical evaluations.