Applying the thresholds for clinical importance for fourteen key domains of the EORTC QLQ-C30: a latent class analysis of cancer survivors

A person’s quality of life is impacted from the beginning of their oncology experience. One of the most common tools to measure quality of life is the EORTC QLQ-C30. The absolute scores it produces can be difficult to interpret in the clinical setting, and thresholds to help identify those who require intervention have recently been introduced. The aim of this research was to identify heterogeneity of these thresholds for clinical importance using latent class analysis in cancer survivors (those undergoing and those who have completed treatment) attending a hospital in the northwest of Ireland. We identified 3 distinct classes of cancer survivors, using Mplus 6.11: high clinical impact (13.9%), compromised physical function (40.3%) and low clinical impact (45.9%). The compromised physical function group were slightly more likely to be older (OR = 1.042, p < .05, CI = 1.000–1.086), not employed (OR = 8.347, p < .01, CI = 2.092–33.305), have lower PG-SGA scores (OR = .826, p < .001, CI = .755–.904), and not have been diagnosed in the last 2 years (OR = .325, p < .05, CI = .114–.923) compared to the high clinical impact group. The low clinical impact group were more likely to be female (OR = 3.288, p < .05, CI = 1.281–1.073), not employed (OR = 10.129, p < .01, CI = 2.572–39.882), have a lower BMI (OR = .921, p < .05, CI = .853–.994), and lower PG-SGA scores (OR = .656, p < .001, CI = .573–.750) than the high clinical impact group. Functional and symptom issues impact on quality of life, and therefore, identifying those of clinical importance is crucial for developing supportive care strategies.