Low Skeletal Muscle Mass Predicts Relevant Outcomes in Palliative Urological Oncology: A Systematic Review and Meta-Analysis.

INTRODUCTION
Low skeletal muscle mass (LSMM) can be assessed by cross-sectional imaging. LSMM is associated with several clinically relevant factors in various disorders with predictive and prognostic implications.


METHODS
Our aim was to establish the effect of computed tomography (CT)-defined LSMM on mortality in renal cell cancer (RCC) and urothelial carcinoma (UC) undergoing palliative treatment. The MEDLINE library, Cochrane, and SCOPUS databases were screened for the associations between CT-defined LSMM up to May 2022. In total, 11 studies were suitable for the analysis.


RESULTS
The included studies comprised 481 patients with RCC and 394 patients with UC. The pooled hazard ratio for the association between LSMM and overall survival was 1.64 (95% CI: 0.90-2.99), p = 0.10 in univariable analysis and 1.55 (95% CI: 0.91-2.63), p = 0.10 in multivariable analysis for RCC. For UC, the pooled hazard ratio was 2.75 (95% CI: 1.77-4.28), p < 0.00001 in univariable, and 2.77 (95% CI: 1.91-4.02), p < 0.00001 in multivariable analysis. For progression-free survival, it was 2.02 (95% CI: 1.24-3.27), p = 0.004 for RCC and 2.43 (95% CI: 1.59-3.74), p < 0.0001 for UC (univariable analysis).


CONCLUSIONS
CT-defined LSMM predicts OS and PFS in RCC and UC in the palliative setting. The effect was higher in UC. Therefore, LSMM assessment should be included as a relevant prognostic biomarker in clinical routine.