Clinic friendly estimation of muscle composition: Preoperative linear segmentation shows overall survival correlated with muscle mass in patients with nonmetastatic renal cell carcinoma

Linear Muscle Segmentation for Metastatic Renal Cell Carcinoma: Changes in Clinic-Friendly Estimation Predict Survival Following Cytoreductive Nephrectomy

INTRODUCTION

Baseline sarcopenia and postoperative changes in muscle mass are independently associated with overall survival (OS) in patients with metastatic renal cell carcinoma (mRCC) undergoing cytoreductive nephrectomy (CN). Here we examine the relationships between preoperative (baseline), postoperative changes in muscle quantity, and survival outcomes following CN as determined by linear segmentation, a clinic-friendly tool that rapidly estimates muscle mass.

MATERIALS AND METHODS

Our nephrectomy database was reviewed for patients with metastatic disease who underwent CN for RCC. Linear segmentation of the bilateral psoas/paraspinal muscles was completed for baseline imaging within 60 days of surgery and imaging 30 to 365 days postoperatively. Kruskal-Wallis for numerical and Fisher's exact test for categorical variables were used to test for differences between groups according to percent change in linear muscle index (LMI, cm2/m2). Multivariable Cox proportional hazards models evaluated associations between LMI percent change and cancer-specific (CSM) and all-cause mortality (ACM). Kaplan Meier curves estimated cancer-specific (CSS) and overall survival (OS).

RESULTS

From 2004-2020, 205 patients were included of whom 52 demonstrated stable LMI (25.4%; LMI change < 5% [0Δ]), 60 increase (29.3%; LMI +5% [+Δ]), and 92 decrease (44.9%; LMI -5% [-Δ]). Median time from baseline imaging to surgery was 18 days, and time from surgery to postoperative imaging was 133 days. Median CSS and OS were highest among patients with 0Δ LMI (CSS: 133.6 [0Δ] vs. 61.9 [+Δ] vs. 37.4 [-Δ] months; P = .0018 || OS: 67.2 [0Δ] vs. 54.8 [+Δ] vs. 29.5 [-Δ] months; P = .0007). Stable LMI was a protective factor for CSM (HR 0.48; P = .024) and ACM (HR 0.59; P = .040) on multivariable analysis.

DISCUSSION

Change in muscle mass after CN, as measured by the linear muscle segmentation technique, is independently associated with OS and CSS in patients following CN. Of note, lack of change was associated with longer survival.

Low Skeletal Muscle as a Risk Factor for Worse Survival in Nonmetastatic Renal Cell Carcinoma with Venous Tumor Thrombus

BACKGROUND

Renal cell carcinoma (RCC) with tumor thrombosis often requires nephrectomy and tumor thrombectomy. As an extensive and potentially morbid operation, patient preoperative functional reserve and body composition is an important consideration. Sarcopenia is a risk factor for increased postoperative complications, systemic therapy toxicity, and death solid organ tumors, including RCC. The influence of sarcopenia in RCC patients with tumor thrombus is not well defined. This study evaluates the prognostic ability of sarcopenia regarding surgical outcomes and complications in patients undergoing surgery for RCC with tumor thrombus.

METHODS

We retrospectively analyzed patients with nonmetastatic RCC and tumor thrombus undergoing radical nephrectomy and tumor thrombectomy. Skeletal muscle index (SMI; cm²/m²) was measured on preoperative CT/MRI. Sarcopenia was defined using body mass index- and sex-stratified thresholds optimally fit via a receiver-operating characteristic analysis for survival. Associations between preoperative sarcopenia and overall (OS), cancer-specific survival (CSS), and 90-day major complications were determined using multivariable analysis.

RESULTS

115 patients were analyzed, with median (IQR) age and body mass index of 69 (56-72) and 28.6 kg/m² (23.6-32.9), respectively. 96 (83.4%) of the cohort had ccRCC. Sarcopenia was associated with shorter median OS (P = .0017) and CSS (P = .0019) in Kaplan-Meier analysis. In multivariable analysis, preoperative sarcopenia was prognostic of shorter OS (HR = 3.38, 95% confidence interval [CI] 1.61-7.09) and CSS (HR = 5.15, 95% CI 1.46-18.18). Notably, 1 unit increases in SMI were associated with improved OS (HR = 0.97, 95% CI 0.94-0.999) but not CSS (HR = 0.95, 95% CI 0.90-1.01). No significant relationship between preoperative sarcopenia and 90-day major surgical complications was observed in this cohort (HR = 2.04, 95% CI 0.65-6.42).

CONCLUSION

Preoperative sarcopenia was associated with decreased OS and CSS in patients surgically managed for nonmetastatic RCC and VTT, however, was not predictive of 90-day major postoperative complications. Body composition analysis has prognostic utility for patients with nonmetastatic RCC and venous tumor thrombus undergoing surgery.

Imaging Techniques to Determine Degree of Sarcopenia and Systemic Inflammation in Advanced Renal Cell Carcinoma

PURPOSE OF REVIEW

The purpose of this review is to provide an up-to-date understanding regarding the literature on sarcopenia and inflammation as prognostic factors in the context of renal cell carcinoma (RCC).

RECENT FINDINGS

Sarcopenia is increasingly recognized as a prognostic factor in RCC. Emerging literature suggests monitoring quantity of muscle on successive imaging and examining muscle density may be additionally informative. Inflammation has prognostic ability in RCC and is also considered a key contributor to development and progression of both RCC and sarcopenia. Recent studies suggest these two prognostic factors together may provide additional prognostic ability when used in combination. Ongoing developments include quality control regarding sarcopenia research and imaging, improving understanding of muscle loss mechanisms, and enhancing clinical incorporation of sarcopenia via improving imaging analysis practicality (i.e., artificial intelligence) and feasible biomarkers. Sarcopenia and systemic inflammation are complementary prognostic factors for adverse outcomes in patients with RCC. Further study on high-quality sarcopenia assessment standardization and expedited sarcopenia assessment is desired for eventual routine clinical incorporation of these prognostic factors.