A pilot study of temsirolimus and body composition

The Current Landscape of Pharmacotherapies for Sarcopenia

Sarcopenia is a skeletal muscle disorder characterized by progressive and generalized decline in muscle mass and function. Although it is mostly known as an age-related disorder, it can also occur secondary to systemic diseases such as malignancy or organ failure. It has demonstrated a significant relationship with adverse outcomes, e.g., falls, disabilities, and even mortality. Several breakthroughs have been made to find a pharmaceutical therapy for sarcopenia over the years, and some have come up with promising findings. Yet still no drug has been approved for its treatment. The key factor that makes finding an effective pharmacotherapy so challenging is the general paradigm of standalone/single diseases, traditionally adopted in medicine. Today, it is well known that sarcopenia is a complex disorder caused by multiple factors, e.g., imbalance in protein turnover, satellite cell and mitochondrial dysfunction, hormonal changes, low-grade inflammation, senescence, anorexia of aging, and behavioral factors such as low physical activity. Therefore, pharmaceuticals, either alone or combined, that exhibit multiple actions on these factors simultaneously will likely be the drug of choice to manage sarcopenia. Among various drug options explored throughout the years, testosterone still has the most cumulated evidence regarding its effects on muscle health and its safety. A mas receptor agonist, BIO101, stands out as a recent promising pharmaceutical. In addition to the conventional strategies (i.e., nutritional support and physical exercise), therapeutics with multiple targets of action or combination of multiple therapeutics with different targets/modes of action appear to promise greater benefit for the prevention and treatment of sarcopenia.

Predictive role of pretreatment skeletal muscle mass index for long-term survival of bladder cancer patients: A meta-analysis

PURPOSE

To identify the predictive role of pretreatment skeletal muscle mass index (SMI) for long-term survival of bladder cancer patients.

METHODS

Several databases were searched for studies investigating the relationship between pretreatment SMI and prognosis in bladder cancer. The overall survival (OS) and cancer-specific survival (CSS) were defined as primary and secondary outcomes, respectively. Hazard ratios (HRs) and 95% confidence intervals (CIs) were combined.

RESULTS

Nine studies involving 1476 cases were included. The results demonstrated that a lower pretreatment SMI was significantly related to poorer OS (HR = 1.56, 95% CI: 1.33-1.82, P<0.001) and subgroup analysis based on thresholds of SMI revealed similar results. Besides, pretreatment SMI was also obviously related to CSS (HR = 1.75, 95% CI: 1.36-2.25, P<0.001).

CONCLUSION

Lower pretreatment SMI was associated with worse long-term survival of bladder cancer patients.

Pre-Therapeutic Sarcopenia among Cancer Patients: An Up-to-Date Meta-Analysis of Prevalence and Predictive Value during Cancer Treatment

This study will address the prevalence of pre-therapeutic sarcopenia (PS) and its clinical impact during cancer treatment among adult cancer patients ≥ 18 years of age. A meta-analysis (MA) with random-effect models was performed via a MEDLINE systematic review, according to the PRISMA statement, focusing on articles published before February 2022 that reported observational studies and clinical trials on the prevalence of PS and the following outcomes: overall survival (OS), progression-free survival (PFS), post-operative complications (POC), toxicities (TOX), and nosocomial infections (NI). A total of 65,936 patients (mean age: 45.7-85 y) with various cancer sites and extensions and various treatment modes were included. Mainly defined by CT scan-based loss of muscle mass only, the pooled prevalence of PS was 38.0%. The pooled relative risks were 1.97, 1.76, 2.70, 1.47, and 1.76 for OS, PFS, POC, TOX, and NI, respectively (moderate-to-high heterogeneity, I²: 58-85%). Consensus-based algorithm definitions of sarcopenia, integrating low muscle mass and low levels of muscular strength and/or physical performance, lowered the prevalence (22%) and heterogeneity (I² < 50%). They also increased the predictive values with RRs ranging from 2.31 (OS) to 3.52 (POC). PS among cancer patients is prevalent and strongly associated with poor outcomes during cancer treatment, especially when considering a consensus-based algorithm approach.

The effect of rapamycin and its analogues on age-related musculoskeletal diseases: a systematic review

BACKGROUND

Preclinical studies have shown a therapeutic role of the mechanistic/mammalian target of rapamycin complex 1 (mTORC1) inhibition with rapamycin and its analogues (rapalogues) on several age-related musculoskeletal disorders (MSKD). However, the applicability to humans of these findings is unknown.

OBJECTIVE

To assess the efficacy of rapalogues on age-related MSKD in humans.

METHODS

We conducted a systematic review according to the PRISMA guidelines. MEDLINE, EMBase, EMCare, and Cochrane Central Registry of Controlled Trials were searched for original studies examining the effects of rapalogues on outcomes linked to the age-related MSKD in humans. This review is registered in the PROSPERO database (University of New York; registration number CRD42020208167).

RESULTS

Fourteen studies met the inclusion criteria and were analyzed. The effect of rapamycin and other rapalogues, including everolimus and temsirolimus, on bone, muscle and joints have been evaluated in humans; however, considerable variability concerning the subjects' age, inclusion criteria, and drug administration protocols was identified. In bone, the use of rapamycin is associated with a decrease in bone resorption markers dependent on osteoclastic activity. In muscle, rapamycin and rapalogues are associated with a reduction in muscle protein synthesis in response to exercise. In the context of rheumatoid arthritis, rapamycin and rapalogues have been associated with clinical improvement and a decrease in inflammatory activity.

CONCLUSION

Although there are studies that have evaluated the effect of rapamycin and rapalogues on MSKD in humans, the evidence supporting its use is still incipient, and the clinical implication of these results on the development of osteoporosis, sarcopenia, or osteosarcopenia has not been studied, opening an interesting field for future research.

Low skeletal muscle mass is a predictor of treatment related toxicity in oncologic patients. A meta-analysis

BACKGROUND & AIMS

The purpose of this meta-analysis was to summarize the published data regarding associations between occurrence of severe treatment related toxicity and low skeletal muscle mass (LSMM) in oncologic patients and to perform a meta-analysis based on a large sample.

METHODS

MEDLINE, Cochrane, and SCOPUS databases were screened for associations between LSMM and treatment related toxicity in oncologic patients up to June 2021. Overall, 48 studies met the inclusion criteria. The following data were extracted: authors, year of publication, study design, number of patients, influence of LSMM on treatment toxicity (odds ratios and confidence intervals). The methodological quality of the involved studies was checked according to the QUADAS instrument. The meta-analysis was undertaken by using RevMan 5.4 software. DerSimonian and Laird random-effects models with inverse-variance weights were used to account for the heterogeneity between the studies.

RESULTS

The included 48 studies comprised 4803 patients with different malignant diseases. LSMM occurred in 1966 patients (40.9%). LSMM was associated with therapy toxicity (simple logistic regression) with an odds ratio OR = 2.19, CI95%= (1.78-2.68). LSMM was associated with DLT in patients underwent curative treatment (16 studies, 2381 patients) with OR = 2.48, CI95%= (1.77-3.48). LSMM predicted DLT in patients underwent palliative chemotherapy (30 studies, 2337 patients)with OR = 2.06, CI95%= (1.56-2.74). In the subgroups received different palliative therapies, relationships between LSMM and DLT were as follows: conventional chemotherapies (7 studies, 600 patients) OR = 2.14, CI95%= (1.38-3.31); different kinases inhibitors (13 studies, 906 patients) OR = 3.08, CI95%= (1.87-5.09); checkpoint inhibitors (7 studies, 557 patients) OR = 1.30, CI95%= (0.79-2.11).

CONCLUSIONS

LSMM is an essential factor of treatment toxicity in oncologic patients. Association between LSMM and DLT is strongest in patients received therapy with kinases inhibitors. The influence of LSMM on DLT is lowest in patients underwent treatment with checkpoint inhibitors. The presence of LSMM should be included into radiological reports and provided to oncologists to optimize chemotherapy. LSMM should be included into dose calculation for chemotherapy.

Impact of BMI on the outcome of metastatic breast cancer patients treated with everolimus: a retrospective exploratory analysis of the BALLET study

INTRODUCTION

Reliable biomarkers of response to mTOR inhibition are yet to be identified. As mTOR is heavily implicated in cell-metabolism, we investigated the relation between BMI variation and outcomes in metastatic breast cancer (mBC) patients treated with everolimus.

RESULTS

we found a linear correlation between everolimus exposure duration and BMI/weight decrease. Patients exhibiting >2 kg weight loss or >3% BMI decrease from baseline at the end of treatment (EOT) had a statistically significant improvement in PFS. Interestingly, a similar BMI/weight decrease within the first 8 weeks of therapy identified patients at higher risk of progression.

PATIENTS AND METHODS

we performed a retrospective analysis of patients enrolled in the BALLET trial who progressed during the study. Primary end-point was progression-free survival (PFS). Secondary end-point was the identification of other predictors of response.

CONCLUSION

A >3% weight loss at EOT is associated with better outcome in mBC patients treated with everolimus. On the contrary, a significant early weight loss represents a predictor of poor survival and could therefore be used as an early negative prognostic marker. As PI3K-inhibition also converges onto mTOR, these findings might extend to patients treated with selective PI3K inhibitors and warrant further investigation.

Chemotherapy-Induced Sarcopenia

OPINION STATEMENT

Sarcopenia is being consistently recognized as a condition not only associated with the presence of a malignancy but also induced by the oncologic therapies. Due to its negative impact on tolerance to chemotherapy and final outcome in both medical and surgical cancer patients, sarcopenia should be always considered and prevented, and, if recognized, should be appropriately treated. A CT scan at the level of the third lumbar vertebra, using an appropriate software, is the more common and easily available way to diagnose sarcopenia. It is now acknowledged that mechanisms involved in iatrogenic sarcopenia are several and depending on the type of molecule included in the regimen of chemotherapy, different pharmacologic antidotes will be required in the future. However, progression of the disease and the associated malnutrition per se are able to progressively erode the muscle mass and since sarcopenia is the hallmark of cachexia, the therapeutic approach to chemotherapy-induced sarcopenia parallels that of cachexia. This approach mainly relies on those strategies which are able to increase the lean body mass and include the use of anabolic/anti-inflammatory agents, nutritional interventions, physical exercise and, even better, a combination of different therapies. There are some phase II studies and some small controlled randomized trials which have validated these treatments using single agents or combined multimodal approaches. While these approaches may require the cooperation of some specialists (nutritionists with a specific knowledge on pathophysiology of catabolic states, accredited exercise physiologists and physiotherapists), the oncologist too should directly enter these issues to coordinate the choice and priority of the treatments. Who better than the oncologist knows the natural history of the disease, its evolution, and the probability of tolerance and response to the oncologic therapy? Only the oncologist knows when it is essential to potentiate any effort to better achieve a control of the disease, using all the available armamentarium, and when the condition is too advanced and hence requires a more palliative than supporting care. The oncologist also knows when to expect a gastrointestinal toxicity (mucositis, nausea, vomiting, and diarrhea) and hence it is more convenient using a parenteral than an enteral nutritional intervention or, on the contrary, when patient is suitable for discharge from hospital and oral supplements should be promptly tested for compliance and then prescribed. When patients are at high risk for malnutrition or if, regardless of their nutritional status, they are candidate to aggressive and potentially toxic treatments, they should undergo a jointed evaluation by the oncologist and the nutritionist and physical therapist to assess together a combined approach. In conclusion, the treatment of both cancer- or chemotherapy-related sarcopenia represents a challenge for the modern oncologist who must be able to coordinate a new panel of specialists with the same skill necessary to decide the priority of different oncologic treatments within a complex multidisciplinary context.

Measurement of Muscle Mass and Sarcopenia Using Anthropometry, Bioelectrical Impedance, and Computed Tomography in Surgical Patients with Colorectal Malignancy: Comparison of Agreement Between Methods

Background: Low skeletal muscle index (SMI) and sarcopenia adversely affect clinical outcomes in oncology patients. Study aims were to assess the agreement of bioelectrical impedance analysis (BIA), mid-arm muscle circumference (MAMC), and computed tomography (CT) at the third lumbar vertebra (L3), for the measurement of muscle mass and identification of sarcopenia, in patients with colorectal cancer (CRC).Method: A comparison study of low SMI and sarcopenia determined by BIA and MAMC, compared to CT. Sensitivity, specificity and area under the curve (AUC) were calculated.Results: CT scans were obtained for 100 participants. Low SMI was identified in 29%, 57%, and 20% of participants using CT at L3, BIA, and MAMC, respectively. For low muscle mass BIA showed 60% of participants were correctly classified (AUC 0.619, sensitivity 80%, specificity 52%, kappa 0.241, P = 0.009) and for MAMC, 73% of participants were correctly classified (AUC 0.625, sensitivity 38%, specificity 88%, kappa 0.286, P = 0.005). There were 14%, 31%, and 10% of participants identified as having sarcopenia from CT, BIA, and MAMC, respectively.Conclusions: Both BIA and MAMC show a poor level of agreement for measuring muscle mass compared to CT scans using L3 in patients with CRC.

Effects of weight loss and sarcopenia on response to chemotherapy, quality of life, and survival

It has frequently been shown that patients with cancer are one of the largest hospital patient groups with a prevalence for malnutrition. Weight loss is a frequent manifestation of malnutrition in patients with cancer. Several large-scale studies over the past 35 y have reported that involuntary weight loss affects 50% to 80% of these patients with the degree of weight loss dependent on tumor site and type and stage of disease. The aim of this review was to determine the consequences of malnutrition, weight loss, and muscle wasting in relation to chemotherapy tolerance, postoperative complications, quality of life, and survival in patients with cancer. The prognostic impact of weight loss on overall survival has long been recognised with recent data suggesting losses as little as 2.4% predicts survival independent of disease, site, stage or performance score. Recently the use of gold-standard methods of body composition assessment, including computed tomography, have led to an increased understanding of the importance of muscle abnormalities, such as low muscle mass (sarcopenia), and more recently low muscle attenuation, as important prognostic indicators of unfavourable outcomes in patients with cancer. Muscle abnormalities are highly prevalent (ranging from 10-90%, depending on cancer site and the diagnostic criteria used). Both low muscle mass and low muscle attenuation have been associated with poorer tolerance to chemotherapy; increased risk of postoperative complications; significant deterioration in a patients' performance status, and poorer psychological well-being, overall quality of life, and survival.

A window beneath the skin: how computed tomography assessment of body composition can assist in the identification of hidden wasting conditions in oncology that profoundly impact outcomes

Advancements in image-based technologies and body composition research over the past decade has led to increased understanding of the importance of muscle abnormalities, such as low muscle mass (sarcopenia), and more recently low muscle attenuation (MA), as important prognostic indicators of unfavourable outcomes in patients with cancer. Muscle abnormalities can be highly prevalent in patients with cancer (ranging between 10 and 90 %), depending on the cohort under investigation and diagnostic criteria used. Importantly, both low muscle mass and low MA have been associated with poorer tolerance to chemotherapy, increased risk of post-operative infectious and non-infectious complications, increased length of hospital stay and poorer survival in patients with cancer. Studies have shown that systemic antineoplastic treatment can exacerbate losses in muscle mass and MA, with reported loss of skeletal muscle between 3 and 5 % per 100 d, which are increased exponentially with progressive disease and proximity to death. At present, no effective medical intervention to improve muscle mass and MA exists. Most research to date has focused on treating muscle depletion as part of the cachexia syndrome using nutritional, exercise and pharmacological interventions; however, these single-agent therapies have not provided promising results. Rehabilitation care to modify body composition, either increasing muscle mass and/or MA should be conducted, and its respective impact on oncology outcomes explored. Although the optimal timing and treatment strategy for preventing or delaying the development of muscle abnormalities are yet to be determined, multimodal interventions initiated early in the disease trajectory appear to hold the most promise.

Prevalence and predictive value of pre-therapeutic sarcopenia in cancer patients: A systematic review

BACKGROUND & AIMS

To assess the prevalence of sarcopenia before cancer treatment and its predictive value during the treatment.

METHODS

We searched MEDLINE via PubMed for articles published from 2008 to 2016 that reported prospective observational or interventional studies of the prevalence of pre-therapeutic sarcopenia and its consequences in adults with cancer who were 18 years or older. Two independent reviewers selected articles based on titles and/or abstracts before a complete review. Sarcopenia had to be measured before cancer treatment. Methods recommended by consensuses (CT scan, MRI, dual X-ray absorptiometry or bio-impedancemetry) to assess sarcopenia were considered. Characteristics of the studies included the prevalence of pre-therapeutic sarcopenia and the prognostic value for outcomes during the cancer treatment.

RESULTS

We selected 35 articles involving 6894 participants (in/out patients, clinical trials). The mean age ranged from 53 to 69.6 years. Pre-therapeutic sarcopenia was found in 38.6% of patients [95% CI 37.4-39.8]. Oesophageal and small-cell lung cancers showed the highest prevalence of pre-therapeutic sarcopenia. Pre-therapeutic sarcopenia was significantly and independently associated with post-operative complications, chemotherapy-induced toxicity and poor survival in cancer patients.

CONCLUSIONS

Pre-therapeutic sarcopenia is highly prevalent in cancer patients and has severe consequences for outcomes of cancer patients.

[Detection and evaluation of the role of sarcopenia in elderly patients with cancer treated with chemotherapy. ONCOSARCO project]

OBJECTIVES

To develop a predictive model of toxicity to chemotherapy in elderly patients with cancer, using the variables associated with sarcopenia, and to identify which of these parameters, sarcopenia or frailty, is the best predictor of toxicity to chemotherapy in the elderly.

MATERIAL AND METHODS

A prospective observational study with patients ≥70 years treated with chemotherapy in the Cancer Unit for the Elderly, in the Medical Oncology Section of the Hospital Virgen de la Luz de Cuenca. The following tests will be performed by each patient before chemotherapy: muscle strength (handgrip, cylindrical handgrip, pinch gauge, hip flexion, knee extension), muscle mass (skeletal muscle mass index), and physical function (gait speed and 5STS test). The occurrence of severe toxicity will be recorded over a period of 4 months of chemotherapy treatment. It will be evaluated, using logistic regression analysis, whether sarcopenia (defined by the European Working Group on Sarcopenia in Older People) or frailty (defined by the phenotype of frailty) is the best predictor of chemotherapy toxicity. Using a multinomial logistic regression analysis, we will try to create the first model to predict toxicity to chemotherapy in elderly patients with diagnosis of cancer, based on the definition of sarcopenia.

CONCLUSIONS

It is expected that the final analysis of this project will be useful to detect predictive factors of toxicity to chemotherapy in elderly patients with cancer.

Muscle wasting associated with the long-term use of mTOR inhibitors

Some targeted therapies alter muscle mass due to interference with pathways of muscle metabolism. The effects of mammalian target of ra pamycin (mTOR) inhibitors on muscle mass have yet to be fully elucidated. In the present study, the computerized tomography (CT) scans of patients receiving mTOR inhibitors for at least 6 months taken at baseline and post-therapy were retrospectively retrieved, and body composition analyses were performed using the software, sliceOmatic version 5.0 (TomoVision, Inc., Magog, QC, Canada). The difference in body composition parameters was evaluated for significance. The time to treatment (TTF) failure was also compared between the sarcopenic and non-sarcopenic patients at the baseline. Of the 75 patients studied, 20 matched the inclusion criteria (including 16 males). The mean duration between the CT scans was 14.4±2.0 months. A total of 12 (60%) patients were sarcopenic at the baseline, whereas three more (75% in total) became sarcopenic following treatment. The use of mTOR inhibitors significantly decreased the skeletal muscle area (P=0.011) and lean body mass (P=0.007), although it had no effect on adipose tissue (P=0.163) or body weight (P=0.262). The rate of skeletal muscle wasting was 2.6 cm²/m², or 2.3 kg in 6 months. The TTF did not differ between sarcopenic and non-sarcopenic patients, and was not significantly associated with any other parameter. To the best of our knowledge, this is the first study to demonstrate that the long-term use of mTOR inhibitors induces a marked loss of muscle mass. Due to the predictive and prognostic role of sarcopenia in cancer patients, these findings may have important clinical implications.

Changes in metabolic profile, iron and ferritin levels during the treatment of metastatic renal cancer - A new potential biomarker?

Metastatic renal cell carcinoma (mRCC) develops in approximately 33% of all renal cancer patients. First line treatment of mRCC includes drugs such as sunitinib, temsirolimus and pazopanib, with overall survival now reaching up to 43,6months in patients with favorable-risk metastatic disease. Several side-effects in mRCC treatment, such as hypothyroidism, can be used as positive prognostic factors and indicate good response to therapy. Hypercholesterolemia and hypertriglyceridemia independent of hypothyroidism are reported as side-effects in temsirolimus treatment and recently in sunitinib treatment, but the exact mechanism and significance of the changes remains elusive. Most likely, metabolic changes are caused by inhibition of mechanistic target of rapamycin (mTOR), a positive target of tumor growth suppression, but also a regulator of iron homeostasis. There are no clinical studies reporting changes in iron and ferritin levels during mRCC biotherapy, but we hypothesize that inhibition of mTOR will also affect iron and ferritin levels. If both lipid and iron changes correlate, there is a high possibility that both changes are primarily caused by mTOR inhibition and the level of change should correlate with the inhibition of mTOR pathway and hence the efficacy of targeted treatment. We lastly hypothesize that mRCC biotherapy causes hypercholesterolemia with a possibly improved cholesterol profile due to increase HDL/LDL ratio, so statins might not have a role as supplementary treatment, whereas a sharp rise in triglyceride levels seems to be the primary target for additional therapy.

Reversible sarcopenia in patients with gastrointestinal stromal tumor treated with imatinib

BACKGROUND

Imatinib is a long-term, oral, targeted therapy for high-risk resected and advanced gastrointestinal stromal tumours (GIST). It is known that sarcopenia affects prognosis and treatment tolerance in patients with various solid cancers. We analysed lumbar skeletal muscle index changes in imatinib-treated GIST patients. Imatinib tolerance was also assessed to evaluate the influence of pre-treatment sarcopenia.

METHODS

Thirty-one patients with advanced (n = 16) or high-risk resected (n = 15) GIST treated with imatinib (400 mg/day) were analysed retrospectively. Lumbar skeletal muscle indexes were evaluated on computed tomography images obtained before starting imatinib for all patients and at 6 months for those initially sarcopenic. Sarcopenia was defined using consensual cutoffs. Imatinib-induced toxicities were assessed after 3 months of administration.

RESULTS

Twelve (38.7%) of the 31 patients were sarcopenic, including one unassessable at 6 months. Seven (63.6%) of the 11 assessable sarcopenic patients became non-sarcopenic after 6 months of imatinib. Pre-treatment sarcopenia was not associated with grades 3-4 toxicities, but the mean number of all-grade toxicities per sarcopenic patient was significantly higher for those non-sarcopenic (4.1 vs. 1.7, respectively, p < 0.01) after 3 months of treatment. Grades 1-2 anaemia and grades 1-2 fatigue were more frequent for sarcopenic than non-sarcopenic patients (83% vs. 26%, P < 0.01 and 42% vs. 5%, P = 0.02, respectively).

CONCLUSIONS

Sarcopenia is reversible in some GIST patients treated with imatinib. Pre-imatinib sarcopenia is predictive of non-severe toxicities, particularly anaemia and fatigue.

Muscle wasting: an overview of recent developments in basic research

The syndrome of cachexia, i.e., involuntary weight loss in patients with underlying diseases, sarcopenia, i.e., loss of muscle mass due to aging, and general muscle atrophy from disuse and/or prolonged bed rest have received more attention over the last decades. All lead to a higher morbidity and mortality in patients, and therefore, they represent a major socio-economic burden for the society today. This mini-review looks at recent developments in basic research that are relevant to the loss of skeletal muscle. It aims to cover the most significant publication of last 3 years on the causes and effects of muscle wasting, new targets for therapy development, and potential biomarkers for assessing skeletal muscle mass. The targets include the following: (1) E-3 ligases TRIM32, SOCS1, and SOCS3 by involving the elongin BC ubiquitin-ligase, Cbl-b, culling 7, Fbxo40, MG53 (TRIM72), and the mitochondrial Mul1; (2) the kinase MST1; and (3) the G-protein Gαi2. D(3)-creatine has the potential to be used as a novel biomarker that allows to monitor actual change in skeletal muscle mass over time. In conclusion, significant development efforts are being made by academic groups as well as numerous pharmaceutical companies to identify new target and biomarker muscles, as muscle wasting represents a great medical need, but no therapies have been approved in the last decades.

Muscle wasting: an overview of recent developments in basic research

The syndrome of cachexia, i.e. involuntary weight loss in patients with underlying diseases, sarcopenia, i.e. loss of muscle mass due to ageing, and general muscle atrophy from disuse and/or prolonged bed rest have received more attention over the last decades. All lead to a higher morbidity and mortality in patients and therefore, they represent a major socio-economic burden for the society today. This mini-review looks at recent developments in basic research that are relevant to the loss of skeletal muscle. It aims to cover the most significant publication of last three years on the causes and effects of muscle wasting, new targets for therapy development and potential biomarkers for assessing skeletal muscle mass. The targets include 1) E-3 ligases: TRIM32, SOCS1 and SOCS3 by involving the elongin BC ubiquitin-ligase, Cbl-b, culling 7, Fbxo40, MG53 (TRIM72) and the mitochondrial Mul1, 2) the kinase MST1 and 3) the G-protein Gαi2. D(3)-creatine has the potential to be used as a novel biomarker that allows to monitor actual change in skeletal muscle mass over time. In conclusion, significant development efforts are being made by academic groups as well as numerous pharmaceutical companies to identify new targets and biomarkers muscle, as muscle wasting represents a great medical need, but no therapies have been approved in the last decades.

The assessment and impact of sarcopenia in lung cancer: a systematic literature review

OBJECTIVES

There is growing awareness of the relationship between sarcopenia (loss of muscle mass and function), and outcomes in cancer, making it a potential target for future therapies. In order to inform future research and practice, we undertook a systematic review of factors associated with loss of muscle mass, and the relationship between muscle function and muscle mass in lung cancer, a common condition associated with poor outcomes.

DESIGN

We conducted a computerised systematic literature search on five databases. Studies were included if they explored muscle mass as an outcome measure in patients with lung cancer, and were published in English.

SETTING

Secondary care.

PARTICIPANTS

Patients with lung cancer.

PRIMARY OUTCOME

Factors associated with loss of muscle mass and muscle function, or sarcopenia, and the clinical impact thereof in patients with lung cancer.

RESULTS

We reviewed 5726 citations, and 35 articles were selected for analysis. Sarcopenia, as defined by reduced muscle mass alone, was found to be very prevalent in patients with lung cancer, regardless of body mass index, and where present was associated with poorer functional status and overall survival. There were diverse studies exploring molecular and metabolic factors in the development of loss of muscle mass; however, the precise mechanisms that contribute to sarcopenia and cachexia remain uncertain. The effect of nutritional supplements and ATP infusions on muscle mass showed conflicting results. There are very limited data on the correlation between degree of sarcopenia and muscle function, which has a non-linear relationship in older non-cancer populations.

CONCLUSIONS

Loss of muscle mass is a significant contributor to morbidity in patients with lung cancer. Loss of muscle mass and function may predate clinically overt cachexia, underlining the importance of evaluating sarcopenia, rather than weight loss alone. Understanding this relationship and its associated factors will provide opportunities for focused intervention to improve clinical outcomes.