Could nutrition status predict fatigue one week before in patients with nasopharynx cancer undergoing radiotherapy?

Abstract Background Patients with nasopharyngeal carcinoma (NPC) undergoing radiotherapy experience significant fatigue, which is frequently underestimated due to the lack of objective indicators for its evaluation. This study aimed to explore the longitudinal association between fatigue and nutrition status 1 week in advance. Methods From January 2021 to June 2022, a total of 105 NPC patients who received intensity‐modulated radiation therapy were enrolled in the observational longitudinal study. The significant outcomes, including the Piper Fatigue Scale‐12 (PFS‐12), the Scored Patient‐Generated Subjective Global Assessment (PG‐SGA), four body composition indices, and the Hospital Anxiety and Depression Scale (HADS), were assessed weekly from pre‐treatment until the completion of radiotherapy (T0–T7) to explore their relationship. Results The trajectories of PFS‐12 and all dimensions for 105 participants reached a peak during the fifth week. Sensory fatigue consistently received the highest scores (T0 = 1.60 ± 2.20, T5 = 6.15 ± 1.57), whereas behavior fatigue exhibited the fastest increase over time (T0 = 1.11 ± 1.86, T5 = 5.47 ± 1.70). Higher PG‐SGA scores were found to be weakly explainable for aggravating fatigue ( β = 0.02 ~ 0.04). Unlike generalized additive mixed models, marginal structural models (MSM) produced larger effect values ( β = 0.12 ~ 0.21). Additionally, body composition indices showed weakly negative relationships with fatigue in MSMs one week in advance. Conclusions The PG‐SGA may be a more accurate predictor of future‐week fatigue than individual body composition indicators, particularly when HADS is controlled for as a time‐dependent confounder.