Body composition is associated with operative and oncologic outcomes in the management of retroperitoneal and trunk soft tissue sarcoma

Background: Sarcopenia, myosteatosis and obesity in cancer may confer negative clinical outcomes, but their prevalence and impact among patients with retroperitoneal and trunk soft tissue sarcoma have not been systematically studied. The aim of this study was to determine body composition among patients with retroperitoneal and trunk sarcoma, and assess impact on operative and oncologic outcomes.

Methods: Consecutive patients undergoing treatment with curative intent from 2009 to 2019 were studied. Subcutaneous fat area and visceral fat areas, intramuscular adipose, lean body mass and fat mass were determined at diagnosis by CT at L3. Univariable and multivariable linear, logistic and Cox proportional hazards regression were performed.

Results: 95 patients (43.2% retroperitoneal, 48.4% trunk, 46.3% multivisceral resection) were studied. Visceral obesity was evident in 47.4%. Postoperative morbidity occurred in 25.9%, with preoperative radiotherapy (OR10.53 [95% CI 1.08-102.39], P = 0.042) and fat mass (OR1.41 [1.12-1.79], P = 0.004) independently predictive on multivariable analysis, while intramuscular adipose independently predicted inpatient LOS (P < 0.001), wound infection (P = 0.024, OR1.20 [1.02-1.40]) and major postoperative morbidity (P = 0.027, OR1.15 [1.02-1.31]). Increasing fat mass, subcutaneous fat area and intramuscular adipose were associated with greater tumor size (all P < 0.01), while intramuscular adipose predicted disease progression during neoadjuvant therapy (P = 0.024), and independently predicted disease specific survival (DSS) (P = 0.005, HR1.11 [1.03-1.20]) and overall survival (OS) on multivariable analysis (P < 0.001, HR1.19 [1.08-1.31]).

Conclusion: Visceral obesity is common in retroperitoneal and trunk sarcoma, and measures of adiposity are associated with adverse operative, but not oncologic outcomes. Myosteatosis is independently associated with postoperative morbidity and adverse oncologic outcomes. Body composition may represent a marker of risk among patients with retroperitoneal and trunk sarcoma.