Skeletal muscle gauge as a prognostic factor in patients with colorectal cancer

Abstract

Background Although skeletal muscle index (SMI) and radiodensity (SMD) are well‐known prognostic factors, the clinical impact of the integrated measure, known as skeletal muscle gauge (SMG), has been limited in patients with colorectal cancer (CRC). Patients and Methods A total of 727 and 268 patients with CRC at two tertiary centers were included and allocated into the training and test sets, respectively. Preoperative slice computed tomography images of the third lumbar area were evaluated for SMI and SMD. SMG was calculated as SMI × SMD and expressed as an arbitrary unit (AU). The optimal cutoff SMG value was determined to maximize the overall survival (OS) difference between the groups with respect to sex in the training set. The multivariate Cox proportional hazard model evaluated the association of its clinical significance. Results With regard to SMG, 1640 and 1523 AU were identified as cutoff values for males and females, respectively. The patients with low SMG values showed significantly worse 5‐year OS than those with high SMG values in the two datasets (both p < 0.001). In the multivariate analysis, low SMG was identified as an independent poor prognostic factor of OS in the training set (hazard ratio 2.18, 95% confidence interval 1.43–3.32, p < 0.001) and test set (hazard ratio 1.79, 95% confidence interval 1.07–3.00, p = 0.025), whereas SMI and SMD were not. Conclusion SMG acts synergistically to improve its prognostic predictive accuracy as compared with SMI or SMD alone in patients with CRC. Additional research is warranted to define its significance in different ethnic groups.

Body composition from single versus multi‐slice abdominal computed tomography: Concordance and associations with colorectal cancer survival

“…Our study confirms that for population research assessing body composition at a single timepoint, single‐slice area measures and multi‐slice volumes are highly concordant and have similar associations with all‐cause mortality; thus, both approaches can be used interchangeably. Indeed, we replicated the known associations of lower SKM quantity 2 , 27 , 28 and radiodensity 29 , 30 , 31 , 32 , 33 , 34 with lower survival using both measurement approaches. With the routine use of CT for surveillance and surgical planning, body composition measurements can be derived for many patients and are consistently associated with a host of clinical outcomes.…”

Prognostic value of computed tomography associated body composition measurement changes in metastatic colorectal cancer patients

“…In some studies, it has been shown that SMI and SMD act as independent prognostic factors in terms of survival (15)(16)(17). Recent studies have also focused on SMG obtained by the integration of SMI and SMD (8,9,16,17).…”

“…In a study investigating the effect of SMG on survival in patients with CRC (8), SMG values were measured only in CT examinations obtained before treatment. It was reported the values in the diagnostic CT scans, but also the follow-up images of the patients.…”

“…Abdominal visceral and subcutaneous fat tissue indices (VATI and SATI) and skeletal muscle index (SMI) were calculated by dividing the VATA, SATA and SMA values, respectively, by the square of the patient's height (m 2 ). The skeletal muscle gauge (SMG) was defined by multiplying the obtained SMI and SMD values (8–10).…”

Prognostic significance of sarcopenia diagnosed based on the anthropometric equation for progression-free survival and overall survival in patients with colorectal cancer

“…Sarcopenia significantly affects the prognosis of patients with malignancies. It is a well-known independent risk factor for poor prognosis in malignancies ( 3 – 6 ). There is a 12–60% prevalence of sarcopenia in CRC patients ( 7 , 8 ).…”