Abstract: PD62-08
Sources of Funding: none

Introduction

Baseline sarcopenia is independently associated with increased mortality after cystectomy for muscle-invasive urothelial carcinoma (MIUC). Cytotoxic chemotherapy is associated with variable changes in lean muscle mass in other malignancies, however, its impact on muscle mass in MIUC patients is undefined. As neoadjuvant chemotherapy (NC) prior to radical cystectomy is the current standard of care in MIUC, our objective was to describe preoperative changes in body composition in patients receiving platinum-based NC.

Methods

Patients with cT2-4, N0-1, M0 UC of the bladder who underwent NC were retrospectively identified. Skeletal muscle index (SMI, cm^2/m^2) was calculated using validated methodology (cross sectional area of skeletal muscle/height^2 at L3) from pre- (pre-NC) and post-NC (post-NC) computed tomography images. Patients were classified as being sarcopenic according to consensus definitions: Male: SMI <55 cm^2/m^2, Female: SMI <38.5 cm^2/m^2. Pre-NC and post-NC median body mass index (BMI) and SMI were compared using paired Wilcoxon signed rank tests.

Results

The cohort consisted of 26 patients, with a median age 70 years, including 7 females (27%). Chemotherapy regimens included dose-dense methotrexate, vinblastine, doxorubicin and cisplatin in 8 (31%), gemcitabine/cisplatin in 16 (62%) and gemcitabine/carboplatin in 1 (3.8%). Median number of cycles was 3.5 (range 2-6). Median pre- and post-NC BMI were 27.1kg/m^2 and 27.2kg/m^2 (p=0.36). Median pre- and post-NC cross-sectional lumbar muscle area were 141 and 129.4 cm^2 (p<0.001). Median pre- and post-NC SMI were 49.2 and 44.5 cm^2/m^2 (p<0.001). Median % change in SMI was -6.4% (Figure). Pre-NC, 18 (69%) patients were sarcopenic vs. 21 (81%, p=0.002) post-NC. Percent change in SMI did not differ according to baseline sarcopenia status or number of chemotherapy cycles.

Conclusions

Although BMI remained stable, we observed a significant decrease in lean muscle mass among MIUC patients treated with platinum-based NC prior to cystectomy, with an associated increase in the prevalence of sarcopenia. These patients may benefit from pre-habilitative interventions to mitigate lean muscle loss prior to cystectomy. The association of change in SMI with surgical outcome in this cohort is under investigation.

Funding

none