Weight loss, phase angle, and survival in cancer patients undergoing radiotherapy: a prospective study with 10-year follow-up.

Background/objectives: Cancer patients undergoing radiotherapy (RT) frequently experience weight loss and changes in body composition, which negatively affect their nutritional status, lead to a poor clinical prognosis, and reduce survival rates. This study aimed to evaluate whether changes in body weight, phase angle, and standardized phase angle are associated with longer survival in cancer patients undergoing RT.

Methods: This prospective cohort study included 62 cancer patients who underwent RT between 2008 and 2009 and were followed until 2019. Anthropometric and bioelectrical impedance analysis data were assessed before and after RT. The Kaplan-Meier method was used to calculate survival, and mortality risk was assessed using the Cox proportional hazards model.

Results: Kaplan-Meier analysis indicated no significant difference in survival time after the 10-year follow-up between patients who had weight loss during RT and those with weight maintenance or weight gain during RT. Mortality risk was associated, in the adjusted multivariate analysis, with age (p = 0.023), site of treatment (p = 0.001), and weight loss during RT (p = 0.044). Every 1 kg lost increased the risk of death by 25% compared with patients who maintained or gained weight during RT. Changes in phase angle and standardized phase angle after RT were not associated with increased mortality risk.

Conclusions: Weight loss during RT, site of treatment, and age are associated with a higher risk of death in cancer patients after the 10-year follow-up.