Sarcopenia, an age-related loss of muscle mass and function, may predict adverse outcomes for patients with urologic cancers. However, the clinical implication and significance of sarcopenic obesity are not well understood. We systematically reviewed data on the prevalence and prognostic impact of sarcopenic obesity for patients with renal cell carcinoma, urothelial carcinoma, and prostate cancer undergoing treatment.
We searched Embase, PubMed/MEDLINE, and Scopus for relevant original articles and abstracts published between January 2010 to February 2021. Primary outcomes were overall survival (OS), cancer-specific survival (CSS), and progression-free survival (PFS). The secondary outcome was the prevalence of sarcopenic obesity.
Fifteen studies comprising 3,866 patients were included. Of the ten studies that evaluated survival outcomes, the association between sarcopenic obesity and survival was mixed. One of ten studies showed a significant association of sarcopenic obesity with OS (HR 0.7, 95%CI 0.51-0.98, p=0.04). One additional study showed reported a trend for shorter OS (p=0.05) associated with sarcopenic obesity. Others reported that it is an adverse prognostic factor for CSS (HR 5.0, 95% CI 1.4-16.7, p=0.01). All other studies did not demonstrate that sarcopenic obesity was of prognostic relevance with regards to OS, CSS, and PFS. Overall, its mean prevalence was 27% (range 11-63).
There is considerable heterogeneity in methods used to define sarcopenic obesity in the literature and current data are limited. Future studies are needed to further understand the relationship of obesity and sarcopenia on the clinical trajectory of patients with urologic cancer.

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