Relationships of Symptom Groups and Functioning Domains in Patients with Advanced-Stage Non-Small Cell Lung Cancer Undergoing Treatment: A Cross-Sectional Study.

The purpose of this study was to describe the symptoms experienced by patients with non-small cell lung cancer (NSCLC), examine whether different symptom groups significantly affected different functioning domains in these patients, and determine the effect of the "lack of energy" and "pain" symptom groups on the different functioning domains of health-related quality of life (HRQOL). From a single tertiary institution, this cross-sectional study enrolled 135 consecutive NSCLC patients who were mostly undergoing chemotherapy and were in the advanced stage (National University Hospital, Daegu, South Korea). Clinical and self-reported demographic information and data on different functioning domains (from the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire C30 (EORTC QLQ-C30)), symptom experience (from the EORTC QLQ-LC13), and the Symptom Distress Scale (SDS) were examined. The four most common symptoms were fatigue (69%), pain (47%), dyspnea (38%), and lack of appetite (36%). The "pain" symptom group was negatively associated with physical, emotional, cognitive, and role functioning. The "lack of energy" symptom group was negatively associated with physical, role, emotional, social, and cognitive functioning. The "lack of energy" symptom group explained the most variance for physical and role functioning, and the "pain" symptom group explained the most variance for emotional functioning. Impaired concentration explained the most variance for cognitive functioning.