Low muscle attenuation is a prognostic factor for survival in metastatic breast cancer patients treated with first line palliative chemotherapy

The Obesity Paradox in Cancer: How Important Is Muscle?

Although higher body mass index (BMI) increases the incidence of many cancers, BMI can also exhibit a null or U-shaped relationship with survival among patients with existing disease; this association of higher BMI with improved survival is termed the obesity paradox. This review discusses possible explanations for the obesity paradox, the prevalence and consequences of low muscle mass in cancer patients, and future research directions. It is unlikely that methodological biases, such as reverse causality or confounding, fully explain the obesity paradox. Rather, up to a point, higher BMI may truly be associated with longer survival in cancer patients. This is due, in part, to the limitations of BMI, which scales weight to height without delineating adipose tissue distribution or distinguishing between adipose and muscle tissue. Thus, cancer patients with higher BMIs often have higher levels of protective muscle. We assert that more precise measures of body composition are required to clarify the relationship of body size to cancer outcomes, inform clinical decision-making, and help tailor lifestyle interventions.

Sarcopenic obesity: hidden muscle wasting and its impact for survival and complications of cancer therapy

Body composition, defined as the proportions and distribution of lean and fat tissues in the human body, is an emergent theme in clinical oncology. Severe muscle depletion (sarcopenia) is most easily overlooked in obese patients; the advent of secondary analysis of oncologic images provides a precise and specific assessment of sarcopenia. Here, we review the definitions, prevalence and clinical implications of sarcopenic obesity (SO) in medical and surgical oncology. Reported prevalence of SO varies due to the heterogeneity in the definitions and the variability in the cut points used to define low muscle mass and high fat mass. Prevalence of SO in advanced solid tumor patient populations average 9% (range 2.3%-14.6%) overall, and one in four (24.7%, range 5.9%-39.2%) patients with body mass index ≥ 30 kg/m2 are sarcopenic. SO is independently associated with higher mortality and higher rate of complications in systemic and surgical cancer treatment, across multiple cancer sites and treatment plans. These associations remain unexplained, however, it has been hypothesized that patients with sarcopenia are generally unfit and unable to tolerate stress. Another proposed mechanism relates to increased exposure to antineoplastic therapy, i.e. a large fat mass would be expected to inflate drug dose in BSA-based treatments, causing an increased rate of dose-limiting toxicity. Pharmacokinetic data are needed to confirm or refute this hypothesis. Old age, deconditioning, cancer progression, acute or chronic nonmalignant disease and drug side-effects are suggested causes of muscle loss, and it is unknown the degree to which this can be reversed. Sarcopenia can be readily detected before start of cancer treatment, however, clinical management protocols for SO patients require development. Studies of cancer treatment dose-modulation are in progress.

Factors Associated with Sarcopenia in Patients with Colorectal Cancer

Introduction; Sarcopenia are frequently observed in cancer patients and was associated with poor prognosis. Objectives; to determine the association of nutritional status, body composition, and clinic parameters with sarcopenia in patients with colorectal cancer (CRC). Methods; We conducted a cross-sectional study of 197 patients with CRC. The sarcopenia elements, including lumbar skeletal muscle index (SMI), handgrip strength, and gait speed were measured. The SMI was assessed by computed tomography at third lumbar vertebra. Phase angle (PA), serum albumin (SAlb), muscle attenuation (MA), and the scored patient-generated subjective global assessment (PG-SGA) were also evaluated. Univariate and multivariate analysis of factors associated with sarcopenia were performed. Results; Sarcopenia was present in 29 of 195 patients (15%) and was significantly correlated with advance age, lower body mass index (BMI), SAlb, PA, MA, higher PG-SGA score, and malnutrition (PG-SGA B). In univariate analysis, age, BMI, SAlb, PA, MA, PG-SGA score, and malnutrition (PG-SGA B) were associated with sarcopenia. Multivariable analysis revealed that BMI, SAlb, PA, MA, and PG-SGA score were independent predictors of sarcopenia. Conclusion; BMI, SAlb, PA, MA, and PG-SGA score were independent predictors of sarcopenia in patients with CRC.

Changes in body composition and muscle attenuation during taxane-based chemotherapy in patients with metastatic breast cancer

PURPOSE

Body composition parameters including low muscle mass, muscle attenuation (which reflects muscle quality) and adipose tissue measurements have emerged as prognostic factors in cancer patients. However, knowledge regarding the possibility of excessive muscle loss during specific systemic therapies is unknown. We describe the changes in body composition and muscle attenuation (MA) during taxane- and anthracycline-based regimens and its association with overall survival (OS) in metastatic breast cancer patients.

METHODS

The lumbar skeletal muscle index (LSMI) was used as marker of muscle mass. LSMI, MA, subcutaneous adipose tissue (SAT), visceral adipose tissue (VAT) and intramuscular adipose tissue (IMAT) were measured before and after first-line treatment with paclitaxel (n = 73) or 5-fluorouracil-doxorubicin-cyclophosphamide (FAC) (n = 25) using CT-images. Determinants of the change of LSMI and MA were analyzed using multiple linear regression. OS was assessed using Cox proportional hazard models.

RESULTS

MA significantly decreased during paclitaxel treatment (- 0.9 HU, p = 0.03). LSMI (p = 0.40), SAT (p = 0.75), VAT (p = 0.84) and IMAT (p = 0.10) remained stable. No significant alterations in body composition parameters during FAC-treatment were observed. Previous (neo-)adjuvant chemotherapy contributed to larger loss of MA during the current treatment. Body composition changes during chemotherapy were not associated with OS.

CONCLUSIONS

MA decreased during treatment with paclitaxel, while muscle mass was stable. Body composition changes are not associated with survival in the absence of progressive disease.

Beyond sarcopenia: Characterization and integration of skeletal muscle quantity and radiodensity in a curable breast cancer population

Skeletal muscle loss, commonly known as sarcopenia, is highly prevalent and prognostic of adverse outcomes in oncology. However, there is limited information on adults with early breast cancer and examination of other skeletal muscle indices, despite the potential prognostic importance. This study characterizes and examines age-related changes in body composition of adults with early breast cancer and describes the creation of a novel integrated muscle measure. Female patients diagnosed with stage I-III breast cancer with abdominal computerized tomography (CT) scans within 12 weeks from diagnosis were identified from local tumor registry (N = 241). Skeletal muscle index (muscle area per height [cm² /m² ]), skeletal muscle density, and subcutaneous and visceral adipose tissue areas, were determined from CT L3 lumbar segments. We calculated a novel integrated skeletal measure, skeletal muscle gauge, which combines skeletal muscle index and density (SMI × SMD). 241 patients were identified with available CT imaging. Median age 52 years and range of 23-87. Skeletal muscle index and density significantly decreased with age. Using literature based cut-points, older adults (≥65 years) had significantly higher proportions of sarcopenia (63 vs 28%) and myosteatosis (90 vs 11%) compared to younger adults (<50 years). Body mass index was positively correlated with skeletal muscle index and negatively correlated with muscle density. Skeletal muscle gauge correlated better with increasing age (ρ = 0.52) than with either skeletal muscle index (ρ = 0.20) or density (ρ = 0.46). Wide variations and age-related changes in body composition metrics were found using routinely obtained abdominal CT imaging. Skeletal muscle index and density provide independent, complementary information, and the product of the two metrics, skeletal muscle gauge, requires further research to explore its impact on outcomes in women with curable breast cancer.

Prognostic Value of Psoas Muscle Area and Density in Patients Who Undergo Cardiovascular Surgery

BACKGROUND

Low skeletal muscle density, determined using computed tomography (CT), has yet to be examined in terms of muscle function and prognostic capability in patients who require open cardiovascular surgery. This study was performed to examine whether psoas muscle area and density, determined using CT, are associated with postoperative mortality in patients who undergo cardiovascular surgery.

METHODS

We reviewed the findings in 773 consecutive patients who underwent preoperative CT imaging, including the level of the third lumbar vertebra for clinical purposes. We measured grip strength, gait speed, and 6-minute walking distance to assess muscle function before hospital discharge. Skeletal muscle area was calculated from psoas muscle cross-sectional area (in squared centimeters) on preoperative CT images at the level of the third lumbar vertebra divided by the square of the patient's height in metres to give the skeletal muscle index (SMI). Skeletal muscle density determined by muscle attenuation (MA) was calculated by measuring the average Hounsfield units of the psoas muscle cross-sectional area.

RESULTS

The mean age of the study population was 65.0 ± 13.1 years, and 64.7% of the patients were male. Multivariate logistic regression analysis and multivariate Cox regression analysis showed that low MA, but not SMI, was significantly associated with muscle function, and all-cause mortality (P < 0.05). Kaplan-Meier analysis showed that low MA, but not low SMI, predicted mortality (P = 0.014).

CONCLUSIONS

Low skeletal muscle density, but not skeletal muscle area, predicted poorer muscle function and mortality in patients who undergo cardiac surgery.

Relationship between Handgrip Strength and Muscle Mass in Female Survivors of Breast Cancer: A Mediation Analysis

This study explored the mediating factors of sarcopenia in a group of women survivors of breast cancer in Bogotá, Colombia. This was a descriptive cross-sectional study with 98 women survivors of breast cancer, who were registered with the SIMMON (Integrated Synergies to Improve Oncological Management in Colombia) Foundation. Body weight, height, and waist circumference (WC) were measured, and body mass index (BMI) was calculated. Body composition (percentage of fat and muscle mass) was evaluated via four-pole bioelectrical impedance analysis. Sarcopenia was defined as low muscle mass plus low grip strength or low gait speed (European Working Group on Sarcopenia in Older People (EWGSOP) criteria). A “causal” mediation analysis with the Baron & Kenny procedure (PROCESS^® macro, Columbus, OH, USA) was used to explore variables related to sarcopenia. Analyses were performed with the IBM SPSS 21 statistical package (SPSS Inc., Chicago, IL, USA). The significance level of the results obtained in the hypothesis contrast was p < 0.05. The mean age of the sample was 65.5 ± 5.9 years, with a BMI of 27.8 ± 4.7 kg/m². The prevalence of sarcopenia was 22.4%. Linear regression models suggest a partial mediation of anthropometric parameters (body mass, body mass index and waist circumference) in the association between handgrip strength and muscle mass. In conclusion, one in every five women survivors of breast cancer had sarcopenia. The findings seem to emphasize the importance of obesity prevention in women survivors of breast cancer, suggesting that high handgrip strength may not relate closely to greater muscle mass and therefore would not exclude the risk of sarcopenia.