Original StudySarcopenia Evaluated Using the Skeletal Muscle Index Is a Significant Prognostic Factor for Metastatic Urothelial Carcinoma
Introduction
In 2012, approximately 430,000 patients were diagnosed with urothelial carcinoma (UC) of urinary bladder, resulting in 160,000 deaths worldwide.1 Metastatic UC is known to be intractable, with a median survival of 14 months, even after implementation of contemporary cisplatin-based chemotherapy regimens.2, 3
Although sarcopenia (age-associated loss of skeletal muscle mass4), is reportedly associated with adverse outcomes in many malignancies,5, 6, 7, 8, 9, 10, 11, 12, 13, 14 to our knowledge, no study has been conducted to investigate its prognostic significance in metastatic UC, despite recent reports associating sarcopenia with outcomes of surgery for localized bladder cancer.12, 13, 14
Moreover, evaluation methods for sarcopenia are not entirely standardized. Although a recent European consensus definition of sarcopenia described computed tomography (CT) and magnetic resonance imaging as gold standards for estimating muscle mass in research,15 several possible alternatives exist. We thus compared several evaluation methods for sarcopenia with special regard to its prognostic values in metastatic UC patients.
Section snippets
Patients
Institutional review board approval was obtained for the study. We reviewed 100 patients with metastatic UC who received first-line systemic chemotherapy at our institution between April 2003 and February 2014. This cohort included 83 patients who were analyzed in our previous study on general prognostic markers.16 Because axial CT images obtained within 30 days before the baseline evaluation were reported to accurately represent muscle status and were recommended for analysis of sarcopenia,17
Results
Of 64 patients, 52 (81%) died of UC during the follow-up, with a median survival time of 13 months (IQR, 9-26 months); 51 (80%) were men and 13 (20%) were women (Table 1). Their median age was 68 years (IQR, 63.3-73 years) at the start of first-line chemotherapy. Primary tumor sites were: bladder, 31 patients (48%); upper urinary tract, 28 (44%); and both, 5 (8%). Forty-two (66%) patients had undergone resection of the primary site, and 17 (27%) had received previous adjuvant chemotherapy.
Discussion
To our knowledge, the present study is the first assessment of the prognostic significance of sarcopenia in patients with metastatic UC. It is also the first to discern that, of the several CT-based methods to evaluate sarcopenia, SMI provides an independent predictor for CSS.
The European consensus definition of sarcopenia described CT and magnetic resonance imaging as gold standards for estimating muscle mass in research.15 However, the optimal evaluation method for sarcopenia has yet to be
Conclusion
Sarcopenia evaluated using the SMI was an independent predictor of poor prognosis for patients with metastatic UC who underwent first-line systemic chemotherapy. Our results might improve stratification of patients and help optimize evaluation of sarcopenia.
Disclosure
The authors have stated that they have no conflicts of interest.
References (25)
- et al.
Prevalence and clinical implications of sarcopenic obesity in patients with solid tumours of the respiratory and gastrointestinal tracts: a population-based study
Lancet Oncol
(2008) - et al.
Impact of sarcopenia on outcomes following resection of pancreatic adenocarcinoma
J Gastrointest Surg
(2012) - et al.
Impact of sarcopenia on outcomes following intra-arterial therapy of hepatic malignancies
J Gastrointest Surg
(2013) - et al.
Sarcopenia as a predictor of complications and survival following radical cystectomy
J Urol
(2014) - et al.
Prognostic value of muscle atrophy in cirrhosis using psoas muscle thickness on computed tomography
J Hepatol
(2014) - et al.
Definition and classification of cancer cachexia: an international consensus
Lancet Oncol
(2011) - et al.
Revised equations for estimated GFR from serum creatinine in Japan
Am J Kidney Dis
(2009) - et al.
Re: Sarcopenia as a predictor of complications and survival following radical cystectomy: A.B. Smith, A.M. Deal, H. Yu, B. Boyd, J. Matthews, E.M. Wallen, R.S. Pruthi, M.E. Woods, H. Muss and M.E. Nielsen J Urol 2014; 191:1714
J Urol
(2014) - et al.
GLOBOCAN 2012 v1.0, Cancer Incidence and Mortality Worldwide
(2013) - et al.
Gemcitabine and cisplatin versus methotrexate, vinblastine, doxorubicin, and cisplatin in advanced or metastatic bladder cancer: results of a large, randomized, multinational, multicenter, phase III study
J Clin Oncol
(2000)