Significance of symptom clustering in palliative care of advanced cancer patients.

Patients with advanced cancer often experience multiple concurrent symptoms. To explore this symptom clustering and its associated parameters, we prospectively surveyed 427 consecutive patients on admission to the Palliative Care Unit. There were 222 males (52.0%) and 205 females (48.0%), with a median age of 66 years (range: 27-93 years). The main tumor sites were lung (19.9%), liver (18.0%), and colorectum (11.0%). The median survival was 13 days (1-418 days). Symptoms were assessed using a face-valid Symptom Reporting Form. We identified five symptom clusters by exploratory factor analysis. Clusters were named "loss of energy," "poor intake," "autonomic dysfunction," "aerodigestive impairment," and "pain complex." We used nonhierarchical cluster analysis to divide the 394 patients with complete data into six groups. Each group was characterized by a particular pattern that was composed of different symptom clusters. Survival, functional performance, bone metastasis, and fluid accumulation were significantly associated with symptom clustering in six groups of patients. The severity of psychological distress also related to their physical deterioration. These data suggest that different underlying mechanisms associate with symptom clustering. Further elucidation of these processes may assist in symptom management.