Skeletal muscle mass as a marker to predict outcomes in children and young adults with cancer.

PURPOSE Nutrition is an important outcome predictor in oncology patients including treatment response, physical disability, quality of life, and overall survival. Sarcopenia (loss of skeletal muscle mass and function) is a demonstrated marker of nutritional status in adults, but data are more limited in children. The purpose of this study was to evaluate whether total psoas muscle area (tPMA) measured at the time of cancer diagnosis predicts overall survival (OS), disease free survival (DFS), or number of days neutropenic. METHODS A retrospective study was performed. tPMA was measured at the L3 and L4 mid-lumbar vertebral body level by a single reviewer on cross-sectional imaging studies performed within 2 weeks of primary oncologic diagnosis for all oncology patients who received their primary therapy at Cincinnati Children's Hospital between 1/1/2000 and 12/31/2013. Spearman's correlation was used to assess the association between tPMA and OS, DFS, days neutropenic, and adjusted days neutropenic. Subanalysis was performed assessing the relationship of tumor type and age at diagnosis with each parameter. RESULTS 164 patients (median age 9.9 years; 89 M/75 F) were included in the study. Days neutropenic and normalized days neutropenic were significantly but weakly negatively correlated with tPMA at L3 (r =  - 0.24, p < 0.002 and r =  - 0.18, p < 0.05 respectively) and L4 (r =  - 0.25, p < 0.002; and and r =  - 0.19, p < 0.02 respectively). At subanalysis, the correlation between anthropometric features and normalized days neutropenic was only seen with brain tumors. There was no statistically significant relationship between sarcopenia at diagnosis and DFS or OS overall or in subanalysis. CONCLUSION There is a weak inverse relationship between days neutropenic and psoas muscle bulk in pediatric and young adult oncology patients suggesting a relationship between nutritional status and cell recovery. Measures of sarcopenia, however, did not correlate with DFS or OS.