Background: 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.
Methods: 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.
Results: 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.
Conclusions: 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.
Keywords: Palliative care; radiotherapy; symptom clusters.