The European Working Group on Sarcopenia in Older People (EWGSOP) revised the consensus in 2018, including that using computed tomography (CT) imaging of the lumbar third vertebra (L3) for the evaluation of muscle mass. However, there is currently discrepancy and confusion in the application of specific cross-sectional and cutoff values for L3. This study aimed to standardize the diagnosis of low muscle mass using L3-CT.

This study included patients who underwent radical gastrectomy for gastric cancer between July 2014 and February 2019. Sarcopenia factors were measured preoperatively. Patients were followed up to obtain actual clinical outcomes. We used the cutoff values obtained based on the inferior aspect of L3-CT images to diagnose sarcopenia in three aspects, respectively. Univariate and multivariate analyses were used to compare long-term and short-term postoperative prognostic differences.

Sarcopenia was found to be an independent risk factor for postoperative complications and overall survival in patients with all three diagnoses of sarcopenia. According to the multivariate model for predicting postoperative complications, patients with inferior-L3 sarcopenia (n = 154,13.8%) had a greater odds ratio (OR) than patients with superior-L3 sarcopenia (n = 220,19.7%) or transverse-L3 sarcopenia (n = 194,17.4%) did (OR, inferior sarcopenia vs. superior sarcopenia, transverse sarcopenia, 2.030 vs. 1.608, 1.679). Furthermore, patients with inferior-L3 sarcopenia had the highest hazard ratio (HR) (HR, inferior sarcopenia vs. superior sarcopenia, transverse sarcopenia, 1.491 vs. 1.408, 1.376) in the multivariate model for predicting overall survival.

We recommend that when diagnosing low muscle mass using L3-CT, the intercepted cross section should be uniform and consistent with the aspect on which the cutoff value is based.

We aimed to examine associations between various sarcopenia indices-including skeletal muscle index (SMI), handgrip strength, lower-extremity muscle strength, a combined measure of handgrip and lower-extremity muscle strength, sarcopenia (defined as a combination of SMI and muscle strength), and the SARC-F questionnaire-and all-cause mortality in patients with advanced or recurrent lung cancer. Moreover, we aimed to identify factors influencing sarcopenia indices that demonstrate strong correlations with prognosis, aiming to inform the development of targeted interventional strategies.

This retrospective observational study enrolled outpatients with lung cancer who underwent chemotherapy. Patients were evaluated for sarcopenia indices, including SMI, handgrip strength, five-repetition sit-to-stand test (5STS), and SARC-F. Physical activity was assessed using the International Physical Activity Questionnaire-Short Form (IPAQ-SF). The log-rank test and Cox proportional hazards model, adjusted for confounders, were used to examine the association between the sarcopenia index and prognosis. Harrell's concordance index (C-index) was used to quantify the predictive power of the resultant model. To examine the significant factors associated with sarcopenia indices, which are associated with prognosis, multivariate logistic regression analysis was performed.

There was a significant association between low handgrip strength (hazard ratio [HR], 2.73; 95% confidence interval [CI], 1.20-6.25; P = 0.017), 5STS ≥ 12 s (low lower-extremity muscle strength) (HR, 2.32; 95% CI, 1.23-4.36; P < 0.01), the combination of low handgrip strength and 5STS ≥ 12 s (HR, 2.37; 95% CI, 1.23-4.57; P = 0.010), and sarcopenia (defined as a combination of SMI and muscle strength) (HR, 2.07; 95% CI, 1.02-4.21; P = 0.044) and survival, whereas there was no significant association between SMI (HR, 1.62; 95% CI, 0.74-3.53; P = 0.20) and SARC-F (HR, 2.07; 95% CI, 0.97-4.43; P = 0.061) and survival. The C-index for handgrip strength and 5STS was 0.625 (95% CI: 0.624-0.627) and 0.635 (95% CI: 0.634-0.636), respectively. Multivariate logistic analysis adjusted for age, sex, clinical stage, and treatment line showed that IPAQ-SF was an independent significant factor associated with 5STS ≥ 12 s (odds ratio [OR], 9.31; 95% CI, 2.93-29.58; P < 0.001), the combination of low handgrip strength and 5STS ≥ 12 s (OR, 6.45; 95% CI, 2.10-19.81; P = 0.001), and sarcopenia (OR, 4.90; 95% CI, 1.52-15.84; P = 0.008).

Handgrip strength and lower-extremity muscle strength were stronger predictors of prognosis compared to the SMI. Furthermore, physical inactivity was significantly associated with lower-extremity muscle strength. From a clinical perspective, evaluating lower-extremity strength and physical activity is essential, and implementing exercise interventions, including strategies to enhance physical activity levels, should be considered.

Myosteatosis, excess muscle fat infiltration, is a novel prognostic factor in cancer patients. To define myosteatosis, skeletal muscle radiodensity (SMD) is most commonly used, while intramuscular adipose tissue (IMAT) is newly introduced. We aimed to compare SMD-defined and IMAT-defined myosteatosis for predicting overall survival (OS) in patients with advanced non-small cell lung cancer (NSCLC) and to explore whether patients with both low SMD and high IMAT had a shorter OS than patients with low SMD or high IMAT alone.

We consecutively and prospectively recruited adult patients with stage IIIB or IV NSCLC at a teaching hospital. The mean SMD of all skeletal muscle areas and the area of IMAT on the unenhanced chest computed tomography (CT) images at the 12th thoracic vertebral level were segmented using Mimics version 21.0. Myosteatosis was defined by either low SMD (SMD-defined myosteatosis) or high IMAT (IMAT-defined myosteatosis). The optimal cutoffs for low SMD and high IMAT were also determined using the maximally selected rank statistics method. We calculated hazard ratios (HRs) and the corresponding confidence intervals (CIs) to evaluate the associations of OS with low SMD, high IMAT, and a combination of them.

We included 565 patients (345 men and 220 women; mean age 58.5 ± 9.0 years). Lower IMAT exhibited a tendency toward a favorable prognosis in men (p = 0.0015) and women (p < 0.0001); whereas higher SMD tended to have a favorable prognosis in men (p = 0.0006) and women (p < 0.0001). At baseline, 423 (74.9 %) participants had high IMAT, 432 (76.5 %) participants had low SMD and 370 (65.5 %) participants had both high IMAT and low SMD. Compared to those without either high IMAT or low SMD, the participants with either high IMAT or low SMD had a shorter OS, while the participants with both High IMAT and Low SMD had the shortest OS (log-rank p < 0.0001). After adjustment for the same confounders, high IMAT (HR, 1.44; 95 % CI, 1.10-1.87) and low SMD (HR, 1.92; 95 % CI, 1.36-2.43) were separately associated with poor prognosis. Moreover, the combination of high IMAT and low SMD indicated a higher risk of poor prognosis (HR, 2.43; 95 % CI, 1.62-3.66).

Both SMD-defined and IMAT-defined myosteatosis are highly prevalent in patients with advanced NSCLC and may serve as independent prognostic factors for OS. The diagnosis of myosteatosis might consider a combination of low SMD and high IMAT because this would help identify patients at a higher risk of mortality.

Sarcopenia, frailty, and malnutrition are associated with undesirable clinical outcomes in cancer patients. Sarcopenia-related measurements may be promising fast biomarkers for frailty. Our objectives were to assess the prevalence of nutritional risk, malnutrition, frailty, and sarcopenia in lung cancer inpatients, and describe the relationship of them.

Stage III and IV lung cancer inpatients were recruited before chemotherapy. The skeletal muscle index (SMI) was assessed by multi-frequency bioelectric impedance analysis (m-BIA). Sarcopenia, frailty, nutritional risk, and malnutrition were diagnosed according to the Asian Working Group for Sarcopenia 2019 (AWGS 2019), Fried Frailty Phenotype (FFP), nutritional risk screening-2002 (NRS-2002), and Global Leadership Initiative on Malnutrition criteria (GLIM), and correlation analysis was performed between them with Pearson's r correlation coefficients. A univariate and multivariate logistic regression analysis was conducted for all patients, gender and age-stratified subgroups to obtain odds ratios (ORs) and 95% confidence intervals (95%CIs).

The cohort included 97 men (77%) and 29 women (23%), with mean age of 64.8 ± 8.7 years. Among the 126 patients, 32 (25.4%) and 41 (32.5%) had sarcopenia and frailty, and the prevalence of nutritional risk and malnutrition was 31.0% (n = 39) and 25.4% (n = 32). Adjusted for age and gender, SMI was correlated with FFP (r = -0.204, p = 0.027), and did not remain significantly when stratified by gender. Stratification according to age revealed in ≥65-years-old population, SMI and FFP were significantly correlated (r = -0.297, p = 0.016), which is not seen in <65-years-old group (r = 0.048, p = 0.748). The multivariate regression analysis showed FFP, BMI, and ECOG were the independent variables associated with sarcopenia (OR 1.536, 95%CI 1.062-2.452, p = 0.042; OR 0.625, 95%CI 0.479-0.815, p = 0.001; OR 7.286, 95%CI 1.779-29.838, p = 0.004).

Comprehensively assessed sarcopenia is independently associated with frailty based on FFP questionnaire, BMI, and ECOG. Therefore, sarcopenia assessment including m-BIA based SMI, and muscle strength and function could be used to indicate frailty to help select the targeting patients for care. Moreover, in addition to muscle mass, muscle quality should not be ignored in clinical practice.

We defined respiratory sarcopenia as a coexistence of respiratory muscle weakness and decreased respiratory muscle mass. Although respiratory muscle function is indispensable for life support, its evaluation has not been included in the regular assessment of respiratory function or adequately evaluated in clinical practice. Considering this situation, we prepared a position paper outlining basic knowledge, diagnostic and assessment methods, mechanisms, involvement in respiratory diseases, intervention and treatment methods, and future perspectives on respiratory sarcopenia, and summarized the current consensus on respiratory sarcopenia. Respiratory sarcopenia is diagnosed when respiratory muscle weakness and decreased respiratory muscle mass are observed. If respiratory muscle mass is difficult to measure, we can use appendicular skeletal muscle mass as a surrogate. Probable respiratory sarcopenia is defined when respiratory muscle weakness and decreased appendicular skeletal muscle mass are observed. If only respiratory muscle strength is decreased without a decrease in respiratory function, the patient is diagnosed with possible respiratory sarcopenia. Respiratory muscle strength is assessed using maximum inspiratory pressure and maximum expiratory pressure. Ultrasonography and computed tomography are commonly used to assess respiratory muscle mass; however, there are insufficient data to propose the cutoff values for defining decreased respiratory muscle mass. It was jointly prepared by the representative authors and authorized by the Japanese Society for Respiratory Care and Rehabilitation, Japanese Association on Sarcopenia and Frailty, Japanese Society of Respiratory Physical Therapy and Japanese Association of Rehabilitation Nutrition. Geriatr Gerontol Int 2023; 23: 5-15.