Measuring quality of life in patients with pleural mesothelioma using a modified version of the Lung Cancer Symptom Scale (LCSS): psychometric properties of the LCSS-Meso

Health-related quality of life (QOL) assessment is a key component in patient assessment and the development of therapies for malignant pleural mesothelioma. However, no mesothelioma-specific instrument was available. The Lung Cancer Symptom Scale (LCSS), a site-specific instrument used to assess QOL in patients with lung cancer, was identified as an instrument that could be appropriate. A modified nine-item patient-reported and six-item observer-reported LCSS was incorporated into two clinical trials of pemetrexed in patients with pleural mesothelioma. Basic psychometric properties of feasibility, reliability, and validity were tested. Properties were stable or enhanced by deletion of the hemoptysis item. Feasibility was demonstrated with a high completion rate of 90% by 512 patients. Reliability was acceptable, with good internal consistency for the eight-item measure (alpha coefficient=0.86) and reasonably good for the five-item observer measure (alpha coefficient=0.66); there was also good stability for the patient measure using test–retest (r=0.87). Content validity was supported by a literature review and patient self-report of presenting symptoms (>90% of patients had three or more symptoms). Construct validity was well supported by finding better scores in the higher performance status groups and greater symptom improvement in patients with tumor response, good concordance with the LCSS conceptual model and good explanation of variance for summation items, and a high degree of convergence between the patient and observer forms (r=0.57). Criterion-related validity was supported by predicting survival time, time to progression, and tumor response rate; all three summary items and the total LCSS-Meso score were statistically significant predictors (p<0.005). The LCSS-Meso is a feasible, reliable, and valid instrument to assess health-related QOL in patients with pleural mesothelioma. One item, hemoptysis, was dropped from the original LCSS based on these findings.