Quality of life in advanced non-small-cell lung cancer: results of a Southwest Oncology Group randomized trial.

PURPOSE

The main purpose of this paper is to present the results of a randomized trial comparing the effects of two chemotherapy regimens on the Quality of life (QOL) of patients with advanced non-small-cell lung cancer (NSCLC). Trials in advanced stage disease represent an important treatment context for QOL assessment. A second purpose of this paper is to examine methods for handling the level of missing data commonly observed in the advanced stage disease context.

METHODS

Patients were randomized to receive cisplatin plus vinorelbine or carboplatin plus paclitaxel. The QOL of 222 patients was assessed with the Functional Assessment of Cancer Therapy-Lung (FACT-L) prior to randomization; follow-up assessments occurred at 13 and 25 weeks. Three methods were used to analyze the QOL data: (1) cross-sectional analysis of four patient categories (improved, stable, missing, and declined) based on changes in the FACT-L score, (2) a mixed linear model, and (3) a pattern mixture model. The longitudinal analyses addressed two potential data biases.

RESULTS

Questionnaire submission rates were 91% at baseline, 68% at 13 weeks, and 47% at 25 weeks. The cross-sectional and mixed linear model analyses did not show significant differences by treatment arm in patient-reported QOL. The pattern mixture model analysis, more appropriate given non-ignorable missing data, also found no statistically significant effect of treatment on patient QOL.

CONCLUSION

We present a sensitivity analysis approach with multiple methods for analyzing treatment effects on patient QOL in the presence of substantial, non-ignorable missing data in an advanced stage disease clinical trial. We conclude that the two treatment arms did not differ statistically in their effects on patient QOL over a 25-week treatment period.