Fat-to-lean mass ratio as a tool to detect the dysmetabolic profile in childhood cancer survivors

Introduction: Survival after childhood cancer has significantly improved in recent decades. Nevertheless, an increased incidence of metabolic syndrome and cardiovascular disease among childhood cancer survivors (CCS) has been reported. The aim of this study was to evaluate whether fat-to-lean mass ratio (FLR) is associated with a dysmetabolic profile in CCS. Methods: At least 2 years from completion of therapy, data from CCS aged 10 to 16 years at follow-up and without any concurrent steroid treatment were collected. Body mass index, waist circumference (WC), WC-to-height ratio, laboratory blood tests, and FLR calculated by dual-energy X-ray absorptiometry measurements were considered. Body mass index >85th percentile and >97th percentile, WC >90th percentile, and WC-to-height ratio > 0.5 were chosen as criteria of overweight and obesity, visceral obesity, and increased cardiovascular risk, respectively. Results: We enrolled 205 CCS previously treated for hematologic cancer or solid or central nervous system tumor. The best cutoff of FLR was 0.6. CCS; those with FLR ≥0.6 (43%) were more frequently overweight and obese (P < 0.001), and presented with higher levels of triglycerides (P = 0.011), homeostatic model assessment for insulin resistance (P = 0.001), alanine transaminase (P = 0.004), and trunk fat (P < 0.001) and lower levels of insulin-like growth factor 1 (P < 0.001) and lean mass (P = 0.009). WC >90th percentile (P = 0.007), insulin-like growth factor 1 (P = 0.002), and trunk fat (P = 0.006) were independent predictors of FLR ≥0.6 in a model including all the previous variables. Conclusions: An increased FLR is suggestive of altered body composition phenotype, allowing identification of CCS at higher risk of metabolic syndrome. Diet and physical activity are needed from commencement of oncological treatments to preserve overall nutritional status and maintain it over the long term.