Muscle wasting in cancer: opportunities and challenges for exercise in clinical cancer trials

Impact of Short-Term Creatine Supplementation on Muscular Performance among Breast Cancer Survivors

Breast cancer (BC) is one of the most common cancers in the United States. Advances in detection and treatment have resulted in an increased survival rate, meaning an increasing population experiencing declines in muscle mass and strength. Creatine supplementation has consistently demonstrated improvements in strength and muscle performance in older adults, though these findings have not been extended to cancer populations.

PURPOSE

The purpose of this study was to investigate the effects of short-term creatine supplementation on muscular performance in BC survivors.

METHODS

Using a double-blind, placebo-controlled, randomized design, 19 female BC survivors (mean ± SD age = 57.63 ± 10.77 years) were assigned to creatine (SUPP) (n = 9) or dextrose placebo (PLA) (n = 10) groups. The participants completed two familiarization sessions, then two test sessions, each separated by 7 days, where the participants supplemented with 5 g of SUPP or PLA 4 times/day between sessions. The testing sessions included sit-to-stand power, isometric/isokinetic peak torque, and upper/lower body strength via 10 repetition maximum (10RM) tests. The interaction between supplement (SUPP vs. PLA) and time (Pre vs. Post) was examined using a group × time ANOVA and effect sizes.

RESULTS

No significant effects were observed for sit-to-stand power (p = 0.471; ηp2 = 0.031), peak torque at 60°/second (p = 0.533; ηp2 = 0.023), peak torque at 120°/second (p = 0.944; ηp2 < 0.001), isometric peak torque (p = 0.905; ηp2 < 0.001), 10RM chest press (p = 0.407; ηp2 = 0.041), and 10RM leg extension (p = 0.932; ηp2 < 0.001). However, a large effect size for time occurred for the 10RM chest press (ηp2 = 0.531) and leg extension (ηp2 = 0.422).

CONCLUSION

Seven days of creatine supplementation does not influence muscular performance among BC survivors.

Obesity worsens mitochondrial quality control and does not protect against skeletal muscle wasting in murine cancer cachexia

BACKGROUND

More than 650 million people are obese (BMI > 30) worldwide, which increases their risk for several metabolic diseases and cancer. While cachexia and obesity are at opposite ends of the weight spectrum, leading many to suggest a protective effect of obesity against cachexia, mechanistic support for obesity's benefit is lacking. Given that obesity and cachexia are both accompanied by metabolic dysregulation, we sought to investigate the impact of obesity on skeletal muscle mass loss and mitochondrial dysfunction in murine cancer cachexia.

METHODS

Male C57BL/6 mice were given a purified high fat or standard diet for 16 weeks before being implanted with 106 Lewis lung carcinoma (LLC) cells. Mice were monitored for 25 days, and hindlimb muscles were collected for cachexia indices and mitochondrial assessment via western blotting, high-resolution respirometry and transmission electron microscopy (TEM).

RESULTS

Obese LLC mice experienced significant tumour-free body weight loss similar to lean (-12.8% vs. -11.8%, P = 0.0001) but had reduced survival (33.3% vs. 6.67%, χ2  = 10.04, P = 0.0182). Obese LLC mice had reduced muscle weights (-24%, P < 0.0354) and mCSA (-16%, P = 0.0004) with similar activation of muscle p65 (P = 0.0337), and p38 (P = 0.0008). ADP-dependent coupled respiration was reduced in both Obese and Obese LLC muscle (-30%, P = 0.0072) consistent with reductions in volitional cage activity (-39%, P < 0.0001) and grip strength (-41%, P < 0.0001). TEM revealed stepwise reductions in intermyofibrillar and subsarcolemmal mitochondrial size with Obese (IMF: -37%, P = 0.0009; SS: -21%, P = 0.0101) and LLC (IMF: -40%, P = 0.0019; SS: -27%, P = 0.0383) mice. Obese LLC mice had increased pAMPK (T172; P = 0.0103) and reduced FIS1 (P = 0.0029) and DRP1 (P < 0.0001) mitochondrial fission proteins, which were each unchanged in Lean LLC. Further, mitochondrial TEM analysis revealed that Obese LLC mice had an accumulation of damaged and dysfunctional mitochondria (IMF: 357%, P = 0.0395; SS: 138%, P = 0.0174) in concert with an accumulation of p62 (P = 0.0328) suggesting impaired autophagy and clearance of damaged mitochondria. Moreover, we observed increases in electron lucent vacuoles only in Obese LLC muscle (IMF: 421%, P = 0.0260; SS: 392%, P = 0.0192), further supporting an accumulation of damaged materials that cannot be properly cleared in the obese cachectic muscle.

CONCLUSIONS

Taken together, these results demonstrate that obesity is not protective against cachexia and suggest exacerbated impairments to mitochondrial function and quality control with a particular disruption in the removal of damaged mitochondria. Our findings highlight the need for consideration of the severity of obesity and pre-existing metabolic conditions when determining the impact of weight status on cancer-induced cachexia and functional mitochondrial deficits.

The complex heterogeneity of immune cell signatures across wasting tissues with C26 and 5-fluorouracil-induced cachexia

Immune cell-driven pathways are linked to cancer cachexia. Tumor presence is associated with immune cell infiltration whereas cytotoxic chemotherapies reduce immune cell counts. Despite these paradoxical effects, both cancer and chemotherapy can cause cachexia; however, our understanding of immune responses in the cachexia condition with cancer and chemotherapy is largely unknown. We sought to advance our understanding of the immunology underlying cancer and cancer with chemotherapy-induced cachexia. CD2F1 mice were given 106 C26 cells, followed by five doses of 5-fluorouracil (5FU; 30 mg/kg LM, ip) or PBS. Indices of cachexia and tumor (TUM), skeletal muscle (SKM), and adipose tissue (AT) immune cell populations were examined using high-parameter flow cytometry. Although 5FU was able to stunt tumor growth, % body weight loss and muscle mass were not different between C26 and C26 + 5FU. C26 increased CD11b+Ly6g+ and CD11b+Ly6cInt inflammatory myeloid cells in SKM and AT; however, both populations were reduced with C26 + 5FU. tSNE analysis revealed 24 SKM macrophage subsets wherein 8 were changed with C26 or C26 + 5FU. C26 + 5FU increased SKM CD11b-CD11c+ dendritic cells, CD11b-NK1.1+ NK-cells, and CD11b-B220+ B-cells, and reduced Ly6cHiCX3CR1+CD206+CD163IntCD11c-MHCII- infiltrated macrophages and other CD11b+Ly6cHi myeloid cells compared with C26. Both C26 and C26 + 5FU had elevated CD11b+F480+CD206+MHCII- or more specifically Ly6cLoCX3CR1+CD206+CD163IntCD11c-MHCII- profibrotic macrophages. 5FU suppressed tumor growth and decreased SKM and AT inflammatory immune cells without protecting against cachexia suggesting that these cells are not required for wasting. However, profibrotic cells and muscle inflammatory/atrophic signaling appear consistent with cancer- and cancer with chemotherapy-induced wasting and remain potential therapeutic targets.NEW & NOTEWORTHY Despite being an immune-driven condition, our understanding of skeletal muscle and adipose tissue immune cells with cachexia is limited. Here, we identified immune cell populations in tumors, skeletal muscle, and adipose tissue in C26 tumor-bearing mice with/without 5-fluorouracil (5FU). C26 and C26 + 5FU had increased skeletal muscle profibrotic macrophages, but 5FU reduced inflammatory myeloid cells without sparing mass. Tumor presence and chemotherapy have contrasting effects on certain immune cells, which appeared not necessary for wasting.

Accelerated loss of lean body mass in head and neck cancer patients during cisplatin-based chemoradiation

BACKGROUND

This study investigated changes in body weight, lean body mass (LBM), fat mass (FM), muscle strength and functional performance during radiation treatment in head and neck cancer (HNSCC) patients. Secondly, it investigated the impact of cisplatin-based chemoradiation (CCRT) on LBM loss compared with radiation alone.

METHODS

48 patients (all tumor sites) received either 6 weeks of radiation alone (n = 16) with 66-68 Gy in 33-34 Fx, 5-6 Fx/week or CCRT, adding weekly cisplatin or carboplatin (n = 32). LBM and FM was evaluated using Dual-energy X-ray Absorptiometry bi-weekly from pre- to two weeks post-treatment. Maximal muscle strength (knee extension, leg - and chest press) and functional performance (stair climb, chair rise, and arm curl) were assessed pre- and post-treatment.

RESULTS

Body weight and LBM had declined significantly already week 2 into treatment and declined significantly further through week 4 and 6 before leveling off after week 6. Bi-weekly, from treatment start to week 2, 2-4, and 4-6, LBM declined 1.2 ± 0.4 kg (p = .002; 95% CI: 0.4;2.0), 2.0 ± 0.4 kg (p < .0001; 1.2;2.8) and 1.4 ± 0.4 kg (p = .001; 0.6;2.2). With a two-week delay, FM declined significantly from week 2-8. All measures of muscle strength declined significantly from pre- to post-treatment. Functional performance was unchanged. LBM loss from pre- to post-treatment was significantly associated with impaired muscle strength (R2 = 0.3-0.5). CCRT patients lost 3.1 ± 0.8 kg of LBM (p = .0001; 1.5;4.7) more from pre- to post-treatment compared with patients receiving radiation alone. Analyses adjusting for nimorazole, tumor stage, baseline BMI, mean radiation dose to constrictor muscles and oral cavity confirmed this.

CONCLUSION

Accelerated and substantial LBM loss was already initiated within the first two weeks of treatment - before the onset of radiation-induced mucositis. LBM loss was associated with muscle strength impairment. Patients receiving CCRT experienced significantly larger LBM loss than patients receiving radiation alone. Registered on clinincaltrials.gov (Identifier: NCT05890859).

The impact of sarcopenia on clinical outcomes in men with metastatic castrate-resistant prostate cancer

INTRODUCTION

Sarcopenia is common in men with metastatic castrate-resistant prostate cancer (mCRPC) and has been largely assessed opportunistically through computed-tomography (CT) scans, excluding measures of muscle function. Therefore, the impact of a comprehensive assessment of sarcopenia on clinical outcomes in men with mCRPC is poorly understood. The objectives of this study were to comprehensively assess sarcopenia through CT scans and measures of muscle function and examine its impact on severe treatment toxicity, time to first emergency room (ER) visit, disease progression, and overall mortality in men initiating chemotherapy or androgen receptor-targeted axis (ARAT) therapy for mCRPC.

METHODS

This was a secondary analysis of a prospective observational study of men with mCRPC at the Princess Margaret Cancer Centre between July 2015-May 2021. Participants were classified as sarcopenic if they had CT-based low muscle mass or low muscle density, a grip strength and gait speed score of <35.5kg and <0.8m/s, respectively, prior to treatment initiation. The impact of sarcopenia on severe treatment toxicity was assessed using multivariable logistic regression. Multivariable Cox regression models were used to determine the impact of sarcopenia on risk of visiting the ER, prostate-specific antigen progression, radiographic progression, and overall mortality.

RESULTS

A total of 110 men (mean age: 74.6) were included in the analysis. At baseline, 30 (27.3%) were classified as sarcopenic. Sarcopenia was a significant predictor of severe toxicity (aOR = 6.26, 95%CI = 1.17-33.58, P = 0.032) and ER visits (aHR = 4.41, 95%CI = 1.26-15.43, p = 0.020) in men initiating ARAT but not in men initiating chemotherapy. Sarcopenia was also a predictor of radiographic progression (aHR = 2.39, 95%CI = 1.06-5.36, p = 0.035) and overall mortality (aHR = 2.44, 95%CI = 1.17-5.08, p = 0.018) regardless of treatment type.

CONCLUSIONS

Baseline sarcopenia predicts radiographic progression and overall mortality in men with mCRPC regardless of the type of treatment and may also predict severe treatment toxicity and ER visits in men initiating ARAT.

Prevalence and mortality risk of low skeletal muscle mass in critically ill patients: an updated systematic review and meta-analysis

Background

Patients with critical illness often develop low skeletal muscle mass (LSMM) for multiple reasons. Numerous studies have explored the association between LSMM and mortality. The prevalence of LSMM and its association with mortality are unclear. This systematic review and meta-analysis was performed to examine the prevalence and mortality risk of LSMM among critically ill patients.

Methods

Three internet databases (Embase, PubMed, and Web of Science) were searched by two independent investigators to identify relevant studies. A random-effects model was used to pool the prevalence of LSMM and its association with mortality. The GRADE assessment tool was used to assess the overall quality of evidence.

Results

In total, 1,582 records were initially identified in our search, and 38 studies involving 6,891 patients were included in the final quantitative analysis. The pooled prevalence of LSMM was 51.0% [95% confidence interval (CI), 44.5-57.5%]. The subgroup analysis showed that the prevalence of LSMM in patients with and without mechanical ventilation was 53.4% (95% CI, 43.2-63.6%) and 48.9% (95% CI, 39.7-58.1%), respectively (P-value for difference = 0.44). The pooled results showed that critically ill patients with LSMM had a higher risk of mortality than those without LSMM, with a pooled odds ratio of 2.35 (95% CI, 1.91-2.89). The subgroup analysis based on the muscle mass assessment tool showed that critically ill patients with LSMM had a higher risk of mortality than those with normal skeletal muscle mass regardless of the different assessment tools used. In addition, the association between LSMM and mortality was statistically significant, independent of the different types of mortality.

Conclusion

Our study revealed that critically ill patients had a high prevalence of LSMM and that critically ill patients with LSMM had a higher risk of mortality than those without LSMM. However, large-scale and high-quality prospective cohort studies, especially those based on muscle ultrasound, are required to validate these findings.

Systematic review registration

http://www.crd.york.ac.uk/PROSPERO/, identifier: CRD42022379200.

Considerations for designing trials targeting muscle dysfunction in exercise oncology

Individuals diagnosed with cancer commonly experience a significant decline in muscle mass and physical function collectively referred to as cancer related muscle dysfunction. This is concerning because impairments in functional capacity are associated with an increased risk for the development of disability and subsequent mortality. Notably, exercise offers a potential intervention to combat cancer related muscle dysfunction. Despite this, research is limited on the efficacy of exercise when implemented in such a population. Thus, the purpose of this mini review is to offer critical considerations for researchers seeking to design studies pertaining to cancer related muscle dysfunction. Namely, 1) defining the condition of interest, 2) determining the most appropriate outcome and methods of assessment, 3) establishing the best timepoint (along the cancer continuum) to intervene, and 4) understanding how exercise prescription can be configured to optimize outcomes.

5-Fluorouracil disrupts skeletal muscle immune cells and impairs skeletal muscle repair and remodeling

5-Fluorouracil (5FU) remains a first-line chemotherapeutic for several cancers despite its established adverse side effects. Reduced blood counts with cytotoxic chemotherapies not only expose patients to infection and fatigue, but can disrupt tissue repair and remodeling, leading to lasting functional deficits. We sought to characterize the impact of 5FU-induced leukopenia on skeletal muscle in the context of remodeling. First, C57BL/6 mice were subjected to multiple dosing cycles of 5FU and skeletal muscle immune cells were assessed. Second, mice given 1 cycle of 5FU were subjected to 1.2% BaCl2 intramuscularly to induce muscle damage. One cycle of 5FU induced significant body weight loss, but only three dosing cycles of 5FU induced skeletal muscle mass loss. One cycle of 5FU reduced skeletal muscle CD45+ immune cells with a particular loss of infiltrating CD11b+Ly6cHi monocytes. Although CD45+ cells returned following three cycles, CD11b+CD68+ macrophages were reduced with three cycles and remained suppressed at 1 mo following 5FU administration. One cycle of 5FU blocked the increase in CD45+ immune cells 4 days following BaCl2; however, there was a dramatic increase in CD11b+Ly6g+ neutrophils and a loss of CD11b+Ly6cHi monocytes in damaged muscle with 5FU compared with PBS. These perturbations resulted in increased collagen production 14 and 28 days following BaCl2 and a reduction in centralized nuclei and myofibrillar cross-sectional area compared with PBS. Together, these results demonstrate that cytotoxic 5FU impairs muscle damage repair and remodeling concomitant with a loss of immune cells that persists beyond the cessation of treatment.NEW & NOTEWORTHY We examined the common chemotherapeutic 5-fluorouracil's (5FU) impact on skeletal muscle immune cells and skeletal muscle repair. 5FU monotherapy decreased body weight and muscle mass, and perturbed skeletal muscle immune cells. In addition, 5FU decreased skeletal muscle immune cells and impaired infiltration following damage contributing to disrupted muscle repair. Our results demonstrate 5FU's impact on skeletal muscle and provide a potential explanation for why some patients may be unable to properly repair damaged tissue.

Nonpharmacological approaches for improving gut resilience to chemotherapy

PURPOSE OF REVIEW

Mucositis of the gastrointestinal tract is a debilitating side effect of chemotherapy that negatively influences treatment tolerance and patient life quality. This review will evaluate the recent literature on nonpharmacological strategies that have the potential to improve chemotherapy-induced mucositis (CIM).

RECENT FINDINGS

Alternatives to pharmacological approaches have shown great promise in preventing CIM. Natural products, including curcumin, ginseng, quercetin, and patchouli all show potential in mitigating CIM. In addition, dietary patterns, such as the elemental diet, high fiber diet, and diets high in amino acids have documented benefits in preventing CIM. Perhaps the greatest advancement coming to this arena in recent years is in the field of probiotics. Indeed, research on single species as well as probiotic mixtures show potential in reducing CIM insofar as probiotics are now being suggested for treatment of CIM by governing bodies. Although behavioral interventions including psychological interventions and exercise interventions have shown promise in reducing cancer therapy-related side effects, more work in this domain is warranted and particularly in the context of CIM.

SUMMARY

Alternatives to pharmacological approaches show great potential for use in prevention and treatment of CIM and should be further developed for use in the clinic.