ABSTRACT
CONTEXT: Pain, fatigue, depression, and sleep disturbance are common in patients with cancer and usually co-occur as a symptom cluster. However, the mechanism underlying this symptom cluster is unclear. OBJECTIVES: This study aimed to identify subgroups of cluster symptoms, compare demographic and clinical characteristics between subgroups, and examine the associations between inflammatory cytokines and cluster symptoms. METHODS: Participants were 170 Chinese inpatients with cancer from two tertiary hospitals. Inflammatory markers including interleukin-6 (IL-6), interleukin-1 receptor antagonist, and tumor necrosis factor alpha were measured. Intergroup differences and associations of inflammatory cytokines with the cluster symptoms were examined with one-way analyses of variance and logistic regression. RESULTS: Based on cluster analysis, participants were categorized into Subgroup 1 (all low symptoms), Subgroup 2 (low pain and moderate fatigue), or Subgroup 3 (moderate-to-high on all symptoms). The three subgroups differed significantly in Eastern Cooperative Oncology Group (ECOG) performance status, sex, residence, current treatment, education, economic status, and inflammatory cytokines levels (all P < 0.05). Compared with Subgroup 1, Subgroup 3 had a significantly poorer ECOG physical performance status and higher IL-6 levels, were more often treated with combined chemoradiotherapy, and were more likely to be rural residents. IL-6 and ECOG physical performance status were significantly associated with 1.246-fold (95% CI 1.114-1.396) and 31.831-fold (95% CI 6.017-168.385) increased risk of Subgroup 3. CONCLUSION: Our findings suggest that IL-6 levels are associated with cluster symptoms in cancer patients. Clinicians should identify patients at risk for more severe symptoms and formulate novel target interventions to improve symptom management.
