Sarcopenia and obesity among patients with soft tissue sarcoma - Association with clinicopathologic characteristics, complications and oncologic outcome: A systematic review and meta-analysis

Background and aims: Sarcopenia and obesity may be associated with negative outcomes in many cancers, but their prevalence and impact in modern regimens for soft-tissue sarcoma (STS) have not been systematically studied. This study summarises and critically evaluates the current evidence-based literature on body mass index (BMI) and body composition among patients with STS, with respect to clinical and pathologic characteristics, treatment-associated morbidity and oncologic outcome.

Methods: A systematic literature search of the PubMed, Embase and Cochrane databases was performed. Meta-analysis of the relationship between BMI, body composition and pathologic characteristics, operative morbidity and oncologic outcome was undertaken using RevMan v.5.4 using fixed or random effects methods as appropriate.

Results: 14 studies including 3598 patients met inclusion criteria. Ten studies reported on BMI, two on CT and two on PET-CT assessment of body composition. BMI ranged from 14.6 to 63.7 kg/m², with obesity in 18%-39% of patients. Although some studies demonstrated larger tumours among patients with obesity, this was not significant on meta-analysis (P = 0.31, I² = 99%). There was no significant difference in tumour grade or histologic type according to BMI. Postoperatively, obesity was associated with increased risk of overall morbidity (odds ratio (OR) 2.03 [95% CI 1.41-2.92], P = 0.0001, I² = 22%), and wound morbidity (OR 1.32 [95% CI 1.02-1.71], P = 0.03, I² = 0%). Similar effects were observed in studies of visceral adiposity. No differences in functional outcomes were observed. There was a trend towards reduced local recurrence among patients with obesity (HR 0.64 [95% CI 0.38-1.08], P = 0.10, I² = 0%), but no difference in distant metastasis (HR 1.00 [95% CI 0.76-1.30], P = 0.98, I² = 0%) or overall survival (HR 0.98 [95% CI 0.43-2.22], P = 0.95, I² = 64%). Various measures of sarcopenia were associated with poorer survival outcomes.

Conclusion: While obesity is associated with increased postoperative morbidity, it had no significant association with long-term oncologic outcomes. Sarcopenia may be associated with a poorer long-term prognosis. A greater understanding of the impact of nutritional status on disease characteristics and treatment outcomes is essential to facilitate improvements in clinical care for patients with STS.