Sleep Disturbances and Health-Related Quality of Life in Paediatric Oncology: A Comparative Study with Non-Oncological Chronic Illness and Healthy Peers

Background/Objectives: Sleep disturbance is increasingly recognized as a key contributor to symptom burden and functioning in paediatric oncology, yet comparative evidence across clinical and healthy populations remains limited. This study examined sleep quality and its association with health-related quality of life (HRQoL) in children and adolescents with cancer compared with peers with non-oncological chronic illnesses and healthy controls. Methods: A cross-sectional study was conducted at Hong Kong Children’s Hospital. Participants 6–18 years were recruited by convenience sampling into three groups (oncology, chronic illness, healthy; n = 50 each). Children and adolescents completed the Chinese Pittsburgh Sleep Quality Index (PSQI) and Pediatrics Quality of Life Inventory (PedsQL) 4.0. Group differences were tested using chi-square tests and one-way analysis of variance (ANOVA) with post hoc Tukey comparisons. Pearson correlations and hierarchical multiple linear regression examined PSQI-PedsQL associations. Results: Sleep quality differed significantly across groups (p < 0.001), with the poorest sleep observed in the oncology group. The prevalence of poor sleep (PSQI ≥ 5) was 60.0% in oncology group, compared with 40.0% in those with chronic illness and 30.0% in healthy peers. Mean global PSQI scores were 6.02 ± 3.40 in the oncology group, 4.10 ± 2.60 in the chronic illness group, and 3.30 ± 2.35 in healthy controls, with a significant overall group difference (p < 0.001). Impairments were most pronounced in sleep latency, habitual sleep efficiency, and sleep disturbances. HRQoL was lowest in the oncology group (p < 0.001). Mean PedsQL total scores were 68.98 ± 15.73 in the oncology group, 75.99 ± 14.03 in the chronic illness group, and 85.44 ± 10.26 in healthy controls, respectively, with a significant overall group difference (p < 0.001). Across the full sample, poor sleep quality was independently associated with lower HRQoL after adjustment for demographic and clinical factors (β = −0.271, p = 0.002), with no significant interaction by group. Conclusions: Children and adolescents with cancer reported clinically significant sleep impairment, driven mainly by reduced sleep quality and continuity. Routine sleep screening and targeted supportive interventions may improve HRQoL in paediatric oncology.