Response of global quality of life to high-dose palliative radiotherapy for non-small-cell lung cancer

Abstract Purpose: To estimate the impact of high-dose palliative radiotherapy treatment (RT) for inoperable non-small cell lung cancer (NSCLC) on the patient's quality of life (QoL) over the remaining survival period, and to compute the number of quality adjusted life days (QALDs) gained. Methods and materials: The QoL of an NSCLC patient is modelled as a function of the days left to live, the days since the start of treatment, a patient specific intercept, and a random error term. Least squares regression analysis is used to fit this model to 376 monthly QoL observations supplied by 42 prospectively enrolled high-dose palliative RT patients with NSCLC. Prediction analysis, based on the regression results and on previously published estimates of the survival response to high-dose palliative RT, is used to compute QALDs gained as a result of treatment. Results: QoL improves steadily over the first 86 days after the start of treatment. This improvement then dissipates to 0 over the subsequent 140 days. Median survival after entry (266 days) yields 158.5 QALDs, of which 56.9 can be attributed treatment: 12.6 as a result of a higher daily QoL and 44.3 as a result of longer survival. Conclusion: Patients with inoperable NSCLC who received high-dose palliative RT, and survived the median 266 days after entry into the study, can attribute about one-third of their 158.5 QALDs to the QoL and survival responses to treatment.