The importance of ethnic-specific cut-offs of low muscle mass for survival prediction in oncology

• Published in: Clinical nutrition (Edinburgh, Scotland) Scotland), 2024-01, Vol.43 (1), p.134-141
• Main Authors: Taguchi, Satoru, Sugawara, Kotaro, Gonoi, Wataru, Hanaoka, Shouhei, Shiomi, Shinichiro, Kishitani, Kenjiro, Uemura, Yukari, Akamatsu, Nobuhiko, Inui, Shohei, Tanaka, Koji, Yagi, Koichi, Kawai, Taketo, Nakagawa, Tohru, Fukuhara, Hiroshi, Abe, Osamu, Seto, Yasuyuki, Gonzalez, M. Cristina, Prado, Carla M., Kume, Haruki
• Format: Article
• Language: English
• Subjects: Cut-off; Definition; Ethnicity; Humans; Low muscle mass; Muscle, Skeletal - diagnostic imaging; Muscle, Skeletal - pathology; Neoplasms - complications; Prognosis; Retrospective Studies; Sarcopenia; Sarcopenia - etiology; Skeletal muscle index; Tomography, X-Ray Computed
• ISSN: 0261-5614; 1532-1983
• DOI: 10.1016/j.clnu.2023.11.029

While skeletal muscle index (SMI) is the most widely used indicator of low muscle mass (or sarcopenia) in oncology, optimal cut-offs (or definitions) to better predict survival are not standardized. We compared five major definitions of SMI-based low muscle mass using an Asian patient cohort with gastrointestinal or genitourinary cancers. We analyzed 2015 patients with surgically-treated gastrointestinal (n = 1382) or genitourinary (n = 633) cancer with pre-surgical computed tomography images. We assessed the associations of clinical parameters, including low muscle mass by each definition, with cancer-specific survival (CSS) and overall survival (OS). During a median follow-up period of 61 months, 303 (15%) died of cancer, and 147 died of other causes. An Asian-based definition diagnosed 17.8% of patients as having low muscle mass, while the other Caucasian-based ones classified most (>70%) patients as such. All definitions significantly discriminated both CSS and OS between patients with low or normal muscle mass. Low muscle mass using any definition but one predicted a lower CSS on multivariate Cox regression analyses. All definitions were independent predictors of lower OS. The original multivariate model without incorporating low muscle mass had c-indices of 0.63 for CSS and 0.66 for OS, which increased to 0.64–0.67 for CSS and 0.67–0.70 for OS when low muscle mass was considered. The model with an Asian-based definition had the highest c-indices (0.67 for CSS and 0.70 for OS). The Asian-specific definition had the best predictive ability for mortality in this Asian patient cohort.