Authors (including presenting author) :
Ho ICH(1), Yuen ECK(1), Yu VMW(1)
Affiliation :
(1)Department of Dietetics, Queen Mary Hospital, Hong Kong
Introduction :
Body weight (BW) loss is inevitable during radiotherapy (RT), the mainstay of Nasopharyngeal Carcinoma (NPC) treatment. Particularly, recent evidence indicated muscle mass (MM) loss during RT was associated with malnutrition, poorer treatment tolerance and increased mortality. While our previous retrospective cohort study demonstrated intensive medical nutrition therapy (MNT) salvaged excessive BW loss among NPC patients undergoing RT, preliminary post-hoc finding revealed more significant weight loss in overweight patients.
Objectives :
This post-hoc analysis, following the cohort study, compared changes in BW and, more importantly, body compositions among underweight, normo-weight and overweight NPC patients undergoing RT, and further explored the associations between pre-RT BW status and the changes in body composition.
Methodology :
The analysis was based on the cohort involving 50 Chinese NPC patients receiving peri-RT intensive MNT at Queen Mary Hospital from January to November 2017. Each patient was reviewed by dietitian at least once throughout RT. Anthropometries including BW, body mass index (BMI), and body composition, namely body fat percentage (pBF) and MM, were measured by a body composition analyser (MC-980, Tanita) during each dietitian outpatient visit.
The percentage changes in BW, BMI, pBF and MM from pre- to post-RT were compared, using ANOVA or non-parametric Kruskal-Wallis H test, between NPC patients stratified into underweight (BMI< 18.5), normo-weight (BMI 18.5-22.9) and overweight (BMI>23.0) groups, based on their pre-RT BMI. Association between pre-RT BMI and the peri-RT percentage changes of the body composition components were analysed via multi-variate linear regression.
Result & Outcome :
Not only did the overweight patients lose significantly more percentage of BW (-8.7±7.6%) throughout RT than both normo-weight (-4.2±3.9%, p=0.033) and underweight (-0.5±5.7%, p=0.003) patients, but also suffered from more prominent loss in MM than underweight patients (-5.7±5.8% Vs -0.5±6.4%, p=0.025).
The inverse association of pre-RT BMI with percentage changes of BW (β=-0.46, p< 0.001) and MM (β=-0.29, p=0.037) in the regression analysis implied the higher the pre-RT BMI, the greater loss in percentage of BW and MM the patients would be expected throughout RT.
This post-hoc analysis has shed new light on that the malnutrition risk of overweight NPC patients undergoing RT, associated with greater MM loss, should not be neglected. It also reiterated the importance of body composition analysis as part of nutritional assessment in addition to BW in nutritional status monitoring.
