Symptom clusters using the EORTC QLQ-C15-PAL in palliative radiotherapy

Patients with advanced cancer often experience a multitude of symptoms. Due to the potential interrelation of symptoms, symptom clusters of 2 or more concurrent symptoms have been advocated for use in the palliative setting to provide better management of symptoms.

The principal component analysis (PCA), exploratory factor analysis (EFA) and hierarchal cluster analysis (HCA) were conducted on responses to items 1-14 in the European Organisation for Research and Treatment of Cancer Quality of Life-C15-Palliative (EORTC QLQ-C15-PAL) at baseline and days 5 and 10 following RT.

There was complete data for 109, 90 and 87 patients at baseline, day 5 and day 10 respectively. The average age was 72 years. The most common site of primary was the prostate (36.7%), and almost all patients presented with bone metastases (95.4%). Analyses identified 2-4 clusters at each interval. From baseline to day 10 follow-up, across all analyses, items associated with physical functioning clustered consistently with shortness of breath. Pain and pain interference clustered with nausea at baseline; and with sleep at both follow-up intervals. Cronbach's alpha values for the clusters ranged from 0.53 to 0.90.

Fluctuation of symptom clusters was observed in a short time frame following palliative RT. Although clusters were dynamic, several items tended to cluster together. Further research is required to validate these clusters.