Introduction and objectives
Sarcopenia (low skeletal muscle mass) is a poor prognostic factor in patients undergoing nephrectomy for localized renal cancer. However, little is known about the trajectory of muscle mass change after surgery. Here, we characterize post-operative changes in muscle mass using a retrospective cohort of patients with clear cell renal cell carcinoma (ccRCC).
Methods
A total of 117 patients with stage II-IV ccRCC who underwent radical nephrectomy from 02/2014-09/2019 at the University of Utah were included. Skeletal muscle (SM) mass area and measures of adiposity (visceral and subcutaneous tissue area) were quantified using standard of care computed tomography (CT) images and Slice-o-matic software (Montreal, Canada). Sarcopenia (yes/no) was classified according to gender-specific international consensus definitions (SMI of <55cm2/m2 for men and <39 cm2/m2 for women). CT images were obtained within 4 months of surgery and at least one scan within 18 months after surgery.
Results
Median age 64 (IQR: 56-71), 74% male, 87% White, 69% had stage II-III and 31% had stage IV disease. At baseline, 48% were obese and 54% were considered sarcopenic. Among 80 patients with evaluable skeletal muscle area, 62 patients maintained muscles mass (± 1 SD, 78%) after surgery and 5 had significant muscle deterioration (≥ 2 SD, 6%).
Conclusions
Among patients with stage II-IV clear cell renal cancer undergoing nephrectomy, post-operative muscle loss was present among 22% of patients and significant muscle loss in 6%. Patients with post-operative muscle wasting after surgery may be an ideal group to target with lifestyle interventions. Among a larger cohort of patients, we plan to assess the association of muscle loss with survival outcomes.
Source of Funding
The research reported in this publication was supported by Huntsman Cancer Foundation.