Resting energy expenditure in lung and colon cancer

Blocking ActRIIB and restoring appetite reverses cachexia and improves survival in mice with lung cancer

Cancer cachexia is a common, debilitating condition with limited therapeutic options. Using an established mouse model of lung cancer, we find that cachexia is characterized by reduced food intake, spontaneous activity, and energy expenditure accompanied by muscle metabolic dysfunction and atrophy. We identify Activin A as a purported driver of cachexia and treat with ActRIIB-Fc, a decoy ligand for TGF-β/activin family members, together with anamorelin (Ana), a ghrelin receptor agonist, to reverse muscle dysfunction and anorexia, respectively. Ana effectively increases food intake but only the combination of drugs increases lean mass, restores spontaneous activity, and improves overall survival. These beneficial effects are limited to female mice and are dependent on ovarian function. In agreement, high expression of Activin A in human lung adenocarcinoma correlates with unfavorable prognosis only in female patients, despite similar expression levels in both sexes. This study suggests that multimodal, sex-specific, therapies are needed to reverse cachexia.

Diverging metabolic programmes and behaviours during states of starvation, protein malnutrition, and cachexia

BACKGROUND

Our evolutionary history is defined, in part, by our ability to survive times of nutrient scarcity. The outcomes of the metabolic and behavioural adaptations during starvation are highly efficient macronutrient allocation, minimization of energy expenditure, and maximized odds of finding food. However, in different contexts, caloric deprivation is met with vastly different physiologic and behavioural responses, which challenge the primacy of energy homeostasis.

METHODS

We conducted a literature review of scientific studies in humans, laboratory animals, and non-laboratory animals that evaluated the physiologic, metabolic, and behavioural responses to fasting, starvation, protein-deficient or essential amino acid-deficient diets, and cachexia. Studies that investigated the changes in ingestive behaviour, locomotor activity, resting metabolic rate, and tissue catabolism were selected as the focus of discussion.

RESULTS

Whereas starvation responses prioritize energy balance, both protein malnutrition and cachexia present existential threats that induce unique adaptive programmes, which can exacerbate the caloric insufficiency of undernutrition. We compare and contrast the behavioural and metabolic responses and elucidate the mechanistic pathways that drive state-dependent alterations in energy seeking and partitioning.

CONCLUSIONS

The evolution of energetically inefficient metabolic and behavioural responses to protein malnutrition and cachexia reveal a hierarchy of metabolic priorities governed by discrete regulatory networks.

Total energy expenditure in patients with colorectal cancer: associations with body composition, physical activity, and energy recommendations

BACKGROUND

Total energy expenditure (TEE) data in patients with early-stage cancer are scarce, precluding an understanding of energy requirements.

OBJECTIVE

The objective was to cross-sectionally characterize TEE in patients with colorectal cancer (CRC) and to compare measured TEE with energy recommendations. It was hypothesized that TEE would differ according to body mass, body composition, and physical activity level (PAL) and current energy recommendations would have poor individual-level accuracy.

METHODS

Patients with newly diagnosed CRC had resting energy expenditure (REE) measured by indirect calorimetry and TEE by doubly labeled water. Hypermetabolism was defined as REE > 110% of that predicted from the Mifflin St.-Jeor equation. Body composition was assessed via DXA. Physical activity was determined as the ratio of TEE to REE (TEE:REE) (PAL) and residual activity energy expenditure (RAEE). TEE was compared with energy recommendations of 25-30 kcal/d and Dietary Reference Intakes (DRIs) using Bland-Altman analyses. Patients were stratified according to median BMI, PAL, and sex-specific ratio of fat mass (FM) to fat-free mass (FFM).

RESULTS

Twenty-one patients (M:F 14:7; mean ± SD BMI: 28.3 ± 4.9 kg/m2, age: 57 ± 12 y) were included. Most (n = 20) had stage II-III disease; 1 had stage IV. Approximately half (n = 11) were hypermetabolic; TEE was not different in those with hypermetabolism and REE as a percentage of predicted was not correlated with TEE. Mean ± SD TEE was 2473 ± 499 kcal/d (range: 1562-3622 kcal/d), or 29.7 ± 6.3 kcal/kg body weight (range: 20.4-48.5 kcal/kg body weight). Mean ± SD PAL was 1.43 ± 0.27. The energy recommendation of 25 kcal/kg underestimated TEE (-12.6% ± 16.5%, P = 0.002); all energy recommendations had wide limits of agreement (the smallest was DRI with measured PAL: -21.2% to 29.3%). Patients with higher BMI and FM:FFM had higher bias using kilocalories per kilogram recommendations; bias from several recommendations was frequently lower (i.e. underestimation) in patients with higher PAL and RAEE.

CONCLUSIONS

TEE variability was not reflected in energy recommendations and error was related to body weight, body composition, and physical activity. This trial was registered at clinicaltrials.gov as NCT03131921.

Persistently Increased Resting Energy Expenditure Predicts Short-Term Mortality in Patients with Acute-on-Chronic Liver Failure

OBJECTIVE

Hypermetabolism based on measurements of resting energy expenditure (REE) is suggested to be a potential biomarker for predicting the clinical outcomes of some diseases. We aimed to evaluate the potential value of hypermetabolism for predicting the short-term (28-day) mortality of patients with hepatitis B virus-related acute-on-chronic liver failure (HBV-ACLF).

METHODS

A total of 105 HBV-ACLF patients, 30 chronic hepatitis B (CHB) patients and 30 healthy controls (HCs) were included in this study. The REE was measured using indirect calorimetry in the morning after 8-10 h of fasting. The predicted REE (REEHB) was determined using Harris-Benedict equation. Persistent hypermetabolism was defined as the REE:REEHB ratio > 1.20 at day 1 and day 7 after admission. The severity of liver disease was estimated using the Model for End-Stage Liver Disease (MELD). Clinical and biochemical variables were determined using blood samples ordered upon admission. These variables were compared between nonsurviving and surviving patients who were classified according to the 28-day mortality.

RESULTS

The frequency of hypermetabolism at baseline was significantly higher in ACLF patients than that in HCs and CHB patients. Forty-six (43.8%) ACLF patients died within follow-up of 28 days. Persistent hypermetabolism (OR 2.10; 95% CI 1.15-3.69; p = 0.002) and MELD score (OR 1.93; 95% CI 1.47-3.51; p = 0.012) were independent predictive indicators of 28-day mortality. Furthermore, the performance of the 2 variables (persistent hypermetabolism and MELD) together with the area under the receiver operating curve (AUROC: 0.819) was significantly better than that of MELD alone -(AUROC: 0.694) for prediction of short-term mortality (p = 0.014).

CONCLUSION

These findings indicate that persistent hypermetabolism is predictive of short-term mortality in this small population.

Resting energy expenditure in critically ill patients: Evaluation methods and clinical applications

Patients on intensive care present systemic, metabolic, and hormonal alterations that may adversely affect their nutritional condition and lead to fast and important depletion of lean mass and malnutrition. Several factors and medical conditions can influence the energy expenditure (EE) of critically ill patients, such as age, gender, surgery, serious infections, medications, ventilation modality, and organ dysfunction. Clinical conditions that can present with EE change include acute kidney injury, a complex disorder commonly seen in critically ill patients with manifestations that can range from minimum elevations in serum creatinine to renal failure requiring dialysis. The nutritional needs of this population are therefore complex, and determining the resting energy expenditure is essential to adjust the nutritional supply and to plan a proper diet, ensuring that energy requirements are met and avoiding complications associated with overfeeding and underfeeding. Several evaluation methods of EE in this population have been described, but all of them have limitations. Such methods include direct calorimetry, doubly labeled water, indirect calorimetry (IC), various predictive equations, and, more recently, the rule of thumb (kcal/kg of body weight). Currently, IC is considered the gold standard.

Relation between hypermetabolism, cachexia, and survival in cancer patients: a prospective study in 390 cancer patients before initiation of anticancer therapy

Background: Cachexia is a major cause of death in cancer patients. The role of hypermetabolism in cancer cachexia remains unclear.Objective: We studied the relation between resting energy expenditure (REE), the estimated energy balance, clinical and biological markers of cachexia, and survival.Design: REE was measured with the use of indirect calorimetry in cancer patients before the initiation of anticancer therapies. Hypermetabolic, normometabolic, and hypometabolic patients were identified with the use of Boothby's standard. Weight loss, performance status (PS), C-reactive protein (CRP), albumin, the nutritional risk index, daily energy intake, energy balance (equal to daily energy intakes minus the REE), and survival were recorded.Results: Of 390 enrolled patients, 49% of subjects were hypermetabolic, 30% of subjects were normometabolic, and 21% of subjects were hypometabolic. Mean daily energy intakes did not differ significantly between the 3 groups. Hypermetabolic patients, compared with normometabolic patients, were more likely to have a negative energy balance [45% compared with 32%, respectively; OR: 1.74 (95% CI: 1.05, 2.91); P = 0.024], weight loss >5% [48% compared with 34%, respectively; OR: 1.83 (95% CI: 1.11, 3.04); P = 0.013], PS ≥2 [40% compared with 29%, respectively; OR: 1.70 (95% CI: 1.01, 2.88); P = 0.038], and CRP concentrations ≥10 mg/L [52% compared with 33%, respectively; OR: 2.2 (95% CI: 1.33, 3.66); P = 0.001]. In metastatic patients, compared with normometabolism, hypermetabolism was associated with a reduced median survival [14.6 compared with 21.4 mo, respectively; OR: 1.48 (95% CI: 1.01, 2.17); P = 0.044].Conclusions: Hypermetabolism is correlated with clinical and biological markers of cancer cachexia and is associated with a shorter survival in metastatic cancer patients. The development of therapeutic strategies that aim to blunt hypermetabolism appears warranted. This trial was registered at www.controlled-trials.com as ISRCTN46152275.

The Cancer Cachexia Syndrome: A Review of Metabolic and Clinical Manifestations

The progressive deterioration in nutrition status frequently seen in cancer patients is often referred to as cancer cachexia. Unlike starvation, in which fat stores from adipose are depleted and protein is spared from skeletal muscle, neither fat nor protein is spared in cachexia. Cachexia affects nearly half of cancer patients, causing the clinical manifestations of anorexia, muscle wasting, weight loss, early satiety, fatigue, and impaired immune response. Cachexia does not only impede the response to chemotherapy but also is a major cause of morbidity and mortality. According to clinical studies, increasing caloric intake does not necessarily reverse cachexia. The pathophysiology of cachexia involves more complex mechanisms than simply caloric deficiency. The process appears to be mediated by circulating catabolic factors, either secreted by the tumor alone or in concert with host-derived factors, such as tumor necrosis factor-alpha (TNF-alpha), interleukins (IL-1 and IL-6), interferon (IFN-y), and leukemia inhibitory factor (LIF). The successful reversal of this process will require in-depth knowledge of the mechanisms involved, which will then enable the development of effective pharmacologic interventions that may not only improve quality of life, but more importantly, improve survival among cancer patients.

Diet and nutrition in cancer survivorship and palliative care

The primary goal of palliative cancer care is typically to relieve suffering and improve quality of life. Most approaches to diet in this setting have focused only on eating as many calories as possible to avoid cachexia. However, as the concept of palliative care has evolved to include all aspects of cancer survivorship and not just end of life care, there is an increasing need to thoughtfully consider diet and nutrition approaches that can impact not only quality of life but overall health outcomes and perhaps even positively affect cancer recurrence and progression. In this regard, there has been a recent emphasis in the literature on nutrition and cancer as an important factor in both quality of life and in the pathophysiology of cancer. Hence, the primary purpose of this paper is to review the current data on diet and nutrition as it pertains to a wide range of cancer patients in the palliative care setting.

Pathophysiology of cancer cachexia: much more than host-tumour interaction?

Cancer cachexia is a syndrome of progressive nutritional depletion which causes significant morbidity and mortality in cancer patients. One of the main pathogenetic mechanisms underlying cancer cachexia is a complex interaction between the host and the tumour. Tumour cells interact with host cells within the tumour mass resulting in the production of catabolic mediators which degrade host tissue. In addition, the host may mount an aberrant metabolic response to the tumour. However, in recent years, it has also been understood that patient factors, including age and levels of physical activity, and the specific mechanics of protein metabolism in cancer patients may also have a significant impact. In this review article, we not only summarise previous knowledge surrounding host-tumour interaction, but we also discuss these broader concepts in the pathogenesis of cancer cachexia. Clinicians should consider such concepts in the design of an effective multimodal therapy for cachexia.

The scientific rationale for optimizing nutritional support in cancer

Cancer patients lose weight as a result of the anorexia-cachexia syndrome, and this weight loss is associated with significant morbidity and mortality. Thus, nutritional support to arrest or reverse weight loss is of paramount importance in the management of Cachexia cancer patients. Persistent tumour-induced metabolic changes result, however, in a suboptimal response to such support, making nutritional maintenance or improvement difficult targets to achieve. Mechanisms involved in the blockade to anabolism in cancer cachexia include alterations in skeletal muscle and hepatic protein metabolism, and reduced physical activity. Mediators underlying these mechanisms of weight loss include proinflammatory cytokines, tumour-specific cachectic factors, and neuroendocrine mediators of muscle catabolism. The complex mix of different mediators renders unimodal nutritional intervention a strategy that is unlikely to succeed completely. Therefore, clinical trials using combination therapies or immunonutrition are required for future success.

Validation of three predictive equations for basal metabolic rate in adults

Objective

To cross-validate three predictive set of equations for basal metabolic rate (BMR) developed by Schofield (Schofield database), Henry (Oxford database) and Cole (Oxford database) using mean values for age, weight, height and BMR of published studies.

Design

Literature review of studies published from 1985 to March 2002.

Setting

All studies selected used appropriate methods and followed conditions that met the criteria established for basal metabolism, were performed in healthy adults, and were not part of the Schofield or Oxford database.

Subjects

A total of 261 groups of men and women from 175 studies were selected and categorised in three age groups (18.5–29.9, 30.0–59.9, ≥60 years old) and three body mass index (BMI) groups (normal weight, overweight and obese).

Results

Linear regression and concordance correlation analysis showed that the three sets of equations had the same association and agreement with measured BMR, across gender, age, and BMI groups. The agreement of all equations was moderate for men and poor for women. The lowest mean squared prediction errors (MSPRs) were given by Henry equations in men and Cole equations in women. Henry and Cole equations gave lower values than Schofield equations, except for men over 60 years of age. Henry equations were the most accurate in men. None of the three equations performed consistently better in women.

Conclusion

These results support the use of Henry equations in men with a wide range of age and BMI. None of the proposed predictive equations seem to be appropriate to estimate BMR in women.

Nutrition intervention using an eicosapentaenoic acid (EPA)-containing supplement in patients with advanced colorectal cancer. Effects on nutritional and inflammatory status: a phase II trial

GOALS

The aim of the study was to assess the impact of an eicosapentanoic acid-containing protein and energy dense oral nutritional supplement (EPA-ONS) on nutritional and inflammatory status, quality of life (QOL), plasma phospholipids (PPL) and cytokine profile, tolerance of irinotecan-containing chemotherapy and EPA-ONS in patients with advanced colorectal cancer (CRC) receiving chemotherapy.

MATERIALS AND METHODS

Patients with advanced CRC having one prior chemotherapy regimen received 480 ml of EPA-ONS daily for 3 weeks before commencing chemotherapy with folinic acid, 5-fluorouracil, irinotecan (FOLFIRI), and continued for 3 cycles of treatment (9 weeks). All assessments including weight, body composition, C-reactive protein (CRP), QOL, dietary intake, PPL and cytokine analyses were performed at baseline, 3 and 9 weeks.

RESULTS

Twenty-three patients were enrolled, 20 completed 3 weeks, and 15 completed 9 weeks. The mean EPA-ONS intake was 1.7 tetrapaks (408 ml) daily. There was a significant increase in mean weight (2.5 kg) at 3 weeks (p=0.03). Lean body mass (LBM) was maintained. Protein and energy intake significantly decreased after the commencement of chemotherapy (protein p=0.003, energy p=0.02). There was a significant increase in energy levels (p=0.03), whilst all other QOL measures were maintained. PPL EPA levels increased significantly over the first 3 weeks. Mean CRP increased by 14.9 mg/L over the first 3 weeks (p=0.004), but decreased to baseline levels by the end of the trial. There was a significant correlation between plasma IL-6 and IL-10 concentrations and survival, and between IL-12 and toxicity.

CONCLUSION

Dietary counseling and the provision of EPA-ONS may result in maintenance of nutritional status and QOL, however randomized trials are required to evaluate the impact of EPA on toxicity from chemotherapy.

Cancer cachexia

Cancer cachexia is a severe debilitating disorder for which there are currently few therapeutic options. It is driven by the release of pro-inflammatory cytokines and cachectic factors by both host and tumour. Over the past few years, basic science advances have begun to reveal the breadth and complexity of the immunological mechanisms involved, and in the process have uncovered some novel potential therapeutic targets. The effectiveness of thalidomide and eicosapentaenoic acid at attenuating weight loss in clinical trials also provides a further rationale for modulating the immune response. We are now entering an exciting period in cachexia research, and it is likely that the next few years will see effective new biological therapies reach clinical practice.

Nutritional Consequences of Radiotherapy in Nasopharynx Cancer Patients

Nasopharynx cancer (NPC) occurs frequently in southern China. Radiotherapy (RT) is the standard treatment for this cancer, and weight loss is commonly observed during and for a prolonged period after RT. The determinants of this phenomenon are not well known. The nutritional status of 38 NPC patients was assessed serially before and for a 6-mo period after RT. Body weight, body composition (by dual X-ray absorptiometry), basal metabolic rate (BMR, by indirect calorimetry), and calorie intake (by 3-day dietary record) were documented at pre-RT (T0), end-RT (T1), 2 mo post-end-RT (T2), and 6 mo post-end-RT (T3). The BMI at end-RT was 21.5 +- 3.7 kg/m2 (range = 13.7-27.9 kg/m2) and was significantly lower than that at pre-RT (P < 0.001). Body weight at T1-T3 was significantly lower than that at T0 (P < 0.001). Mean percentage weight loss was 10.8% at end-RT. Fifty-five percent of patients (20 of 30) had 10% weight loss by the end of RT. BMR corrected for body weight did not change significantly among the four time points, but BMRs corrected for lean body mass at T2 and T3 were significantly lower than that at T0 (P < 0.01). Patients' calorie intake generally declined from T0 to T1 (from 1,857 P < 411 kcal to 11,68 +- 549 kcal, P < 0.001) and then increased from T1 to T3. The calorie intakes at T2 and T3 were not significantly different from that at T0 but were significantly higher than that at T1. Patients were in negative energy balance before, during, and up until 6 mo after RT. The recovery in body weight lagged behind the recovery of dietary intake. Eighty-two percent of NPC patients had significant weight loss and was in negative energy balance at the end of RT, which persisted for at least 6 mo. This finding suggests that there is room for improvement in the nutritional status of patients with NPC treated with RT.

Research methodology: cancer cachexia syndrome

Cachexia is a syndrome and therefore does not have a specific definition. Patients are characterized by the presence of anorexia, early satiety, weight loss, weakness, anaemia and oedema. These features occur to a variable extent in different patients and may change in severity during the course of a patient's illness. The multifactorial origin of cachexia precludes a uniform pathophysiological definition. Taken together these factors have hindered clinical studies both at a fundamental level and in terms of the introduction of effective therapy. The advent of novel therapeutic targets (e.g., ubiquitin-proteasome pathway) and biological response modifiers has opened possibilities for new clinical trials in cachexia. Regulatory authorities feel it is important not only to demonstrate efficacy in terms of patients' nutritional status (e.g., lean body mass) but also functional status (e.g., performance status). This article reviews current methods to assess the latter. Methods focused on measuring physical activity level (e.g., doubly labelled water technique or physical activity meters) promise objective data which can be readily interpreted in terms of clinically meaningful benefit.

Nutritional support in cancer patients

This article will summarize the current nutrition strategies in cancer patients. A review of relevant studies dealing with nutrition in cancer patients is presented. Basic recommendations for feeding patients with malignancy are suggested. Early nutrition evaluation, assessment, and support should be instituted in the appropriate clinical setting. Use of specialized nutrition support is not indicated in well-nourished cancer patients undergoing surgery, chemotherapy, or radiotherapy in whom adequate oral intake is anticipated. Severely malnourished patients need early nutrition support preoperatively. Postoperative nutrition support has to be initiated in a timely fashion depending on the disease process. An algorithm for decisions regarding administration of specialized nutrition support is proposed.

Do patients with nonmetastatic non-small cell lung cancer demonstrate altered resting energy expenditure?

BACKGROUND

The cancer cachexia syndrome occurs in patients with non-small cell lung cancer (NSCLC) and includes elevated resting energy expenditure (REE). This increase in REE leads to weight loss, which in turn confers a poor prognosis. This study was undertaken to determine whether the cancer cachexia syndrome occurs in patients with nonmetastatic NSCLC.

METHODS

In this case-control study, 18 patients with nonmetastatic NSCLC (stages IA to IIIB) were matched to healthy controls on age (+/- 5 years), gender, and body mass index (+/- 3 kg/m2). Only 4 cancer patients had experienced > 5% weight loss. Cancer patients and controls were compared on the basis of: (1) unadjusted REE, as measured by indirect calorimetry; (2) REE adjusted for lean body mass, as measured by dual x-ray absorptiometry; (3) REE adjusted for body cell mass, as measured by potassium-40 measurement; and (4) REE adjusted for total body water, as measured by tritiated water dilution.

RESULTS

We observed no significant difference in unadjusted REE or in REE adjusted for total body water. However, with separate adjustments for lean body mass and body cell mass, cancer patients manifested an increase in REE: mean difference +/- standard error of the mean: 140+/-35 kcal/day (p = 0.001) and 173+/-65 kcal/day (p = 0.032), respectively. Further adjustment for weight loss yielded similarly significant results.

CONCLUSIONS

These results suggest that the cancer cachexia syndrome occurs in patients with nonmetastatic NSCLC and raise the question of whether clinical trials that target cancer cachexia should be initiated before weight loss.

Metabolic responses to tumour disease and progression: tumour-host interaction

The progressive nutritional deterioration frequently found in cancer patients, is often referred to as cancer cachexia. In contrast to starvation, where it is possible to reverse the body composition changes by the provision of extra calories, in cancer cachexia this reversal is not observed, suggesting that anorexia alone is unlikely to be responsible for this wasting syndrome. Over the past decades a number of studies have focused on the possible mediators which may be responsible for metabolic abnormalities observed in cancer patients. Pro-inflammatory cytokines have been strongly implicated, but evidence supporting such a direct role is lacking. Recently, exciting work regarding molecules produced by tumour cells, and which may induce lipolysis and proteolysis, has been published. There is also evidence that increased metabolism of host resources may provide substrates which might promote tumour growth. A number of studies have demonstrated that polyunsaturated fatty acids, such as linoleic and arachidonic acid, are able to promote tumour cell growth either by directly stimulating mitosis or by inhibiting apoptosis. Even more interesting is the discovery of antagonists of these catabolic factors such as eicosapentanoic acid for the lipolytic factor, which may play a role in the treatment of these patients in the near future.

Nutritional support of the cancer patient: issues and dilemmas

Malnutrition in cancer patients results from multifactorial events and is associated with an alteration of quality of life and a reduced survival. A simple nutritional assessment program and early counselling by a dietitian are essential to guide nutritional support and to alert the physician to the need for enteral (EN) or parenteral nutrition (PN). A daily intake of 20-35 kcal/kg, with a balanced contribution of glucose and lipids, and of 0.2-0.35 g nitrogen/kg is recommended both for EN and PN, with an adequate provision of electrolytes, trace elements and vitamins. EN, always preferable for patients with an intact digestive tract, and PN are both safe and effective methods of administering nutrients. The general results in clinical practice suggest no tumor growth during nutritional support. The indiscriminate use of conventional EN and PN is not indicated in well-nourished cancer patients or in patients with mild malnutrition. EN or PN is not clinically efficacious for patients treated with chemotherapy or radiotherapy, unless there are prolonged periods of GI toxicity, as in the case of bone marrow transplant patients. Severely malnourished cancer patients undergoing major visceral surgery may benefit from perioperative nutritional support, preferably via enteral access. Nutritional support in palliative care should be based on the potential risks and benefits of EN and PN, and on the patient's and family's wishes. Research is currently directed toward the impact of nutritional pharmacology on the clinical outcome of cancer patients. Glutamine-supplemented PN is probably beneficial in bone marrow transplant patients. Immune diets are likely to reduce the rate of infectious complications and the length of hospital stay after GI surgery. Further studies are needed to determine the efficacy of such novel approaches in specific populations of cancer patients, and should also address the question of the overall cost-benefit ratio of nutritional pharmacology, and the effect of nutritional support on length and quality of life.

The prognostic effect of increased resting energy expenditure prior to treatment for lung cancer

OBJECTIVE

Increased resting energy expenditure (REE) is thought to confer a poor prognosis in patients with non-small cell lung cancer (NSCLC). However, no study has validated this hypothesis to date. This study's objective was to examine the prognostic significance of REE in NSCLC.

METHODS

Seventeen patients with NSCLC (stages IA-IIIB) underwent measurement of REE with indirect calorimetry before the initiation of cancer treatment. Similar measurements were performed in 17 control subjects, each of whom was matched to a cancer patient by age ( +/-5 years), sex and body mass index ( +/-3 kg/m2). Patients were classified as hypermetabolic or hypometabolic based on a direct comparison of measured REE between cancer patients and their matched controls. After cancer treatment, these 17 patients were followed for evidence of metastatic disease for up to 32 months.

RESULTS

Six patients developed metastatic disease. The eight hypometabolic cancer patients had a significantly shorter mean disease-free survival compared to the nine hypermetabolic cancer patients: 19 months (95% confidence interval (CI) 12, 26) versus 29 months (95% CI 24, 34), respectively (P < 0.05 by log-rank test). In contrast, Cox regression showed no relationship between disease-free survival and differences in REE between cancer patients and their matched controls (P = 0.20).

CONCLUSIONS

These results suggest that hypermetabolism may predict a longer disease-free survival in NSCLC patients. This finding differs from the prevailing hypothesis that hypometabolic patients with NSCLC survive longer, and deserves further investigation.

Wasting in cancer

Progressive weight loss is a common feature of many types of cancer and is responsible not only for a poor quality of life and poor response to chemotherapy, but also a shorter survival time than is found in patients with comparable tumors without weight loss. Although anorexia is common, a decreased food intake alone is unable to account for the changes in body composition seen in cancer patients, and increasing nutrient intake is unable to reverse the wasting syndrome. Although energy expenditure is increased in some patients, cachexia can occur even with a normal energy expenditure. Various factors have been investigated as mediators of tissue wasting in cachexia. These include cytokines such as tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), interferon-gamma (IFN-gamma) and leukemia inhibitory factor (LIF), as well as tumor-derived factors such as lipid mobilizing factor (LMF) and protein mobilizing factor (PMF), which can directly mobilize fatty acids and amino acids from adipose tissue and skeletal muscle respectively. Induction of lipolysis by the cytokines is thought to result from an inhibition of lipoprotein lipase (LPL), although clinical studies provide no evidence for an inhibition of LPL in the adipose tissue of cancer patients. Instead there is an increased expression of hormone sensitive lipase, the enzyme activated by LMF. Protein degradation in cachexia is associated with an increased activity of the ATP-ubiquitin-proteasome pathway. The biological activity of both the LMF and PMF was shown to be attenuated by eicosapentaenoic acid (EPA). Clinical studies show that this polyunsaturated fatty acid is able to stabilize the rate of weight loss and adipose tissue and muscle mass in cachectic patients with unresectable pancreatic cancer. Knowledge of the mechanism of cancer cachexia should lead to the development of new therapeutic agents.

Biology of cachexia

About half of all cancer patients show a syndrome of cachexia, characterized by loss of adipose tissue and skeletal muscle mass. Such patients have a decreased survival time, compared with the survival time among patients without weight loss, and loss of total body protein leads to substantial impairment of respiratory muscle function. These changes cannot be fully explained by the accompanying anorexia, and nutritional supplementation alone is unable to reverse the wasting process. Despite a falling caloric intake, patients with cachexia frequently show an elevated resting energy expenditure as a result of increases in Cori cycle (i.e., catalytic conversion of lactic acid to glucose) activity, glucose and triglyceride-fatty acid cycling, and gluconeogenesis. A number of cytokines, including tumor necrosis factor-apha, interleukins 1 and 6, interferon gamma, and leukemia-inhibitory factor, have been proposed as mediators of the cachectic process. However, the results of a number of clinical and laboratory studies suggest that the action of the cytokines alone is unable to explain the complex mechanism of wasting in cancer cachexia. In addition, cachexia has been observed in some xenograft models even without a cytokine involvement, suggesting that other factors may be involved. These probably include catabolic factors, which act directly on skeletal muscle and adipose tissue and the presence of which has been associated with the clinical development of cachexia. A polyunsaturated fatty acid, eicosapentaenoic acid, attenuates the action of such catabolic factors and has been shown to stabilize the process of wasting and resting energy expenditure in patients with pancreatic cancer. Such a pharmacologic approach may provide new insights into the treatment of cachexia.

Cancer cachexia: metabolic alterations and clinical manifestations

Progressive wasting is common in many types of cancer and is one of the most important factors leading to the early death of cancer patients. Although anorexia frequently accompanies cachexia it has been difficult to establish a simple cause-and-effect relationship, and nutritional supplementation is not able to effectively reverse the process of cachexia. An increased resting energy expenditure may contribute to weight loss in some cancer patients and may explain the increased oxidation of fat. Futile energy-consuming cycles, such as the Cori cycle, may contribute to the increased energy demand. Unlike starvation, weight loss in cancer arises equally from loss of muscle and fat, and the process is characterized by an increased catabolism of skeletal muscle and a decrease in protein synthesis. Several experimental studies have suggested a role for the cytokines tumor necrosis factor alpha, interleukins-1 and -6, and interferon gamma as mediators of the process of cachexia, although conclusive data supporting a role in human disease are often lacking. Catabolic factors capable of direct breakdown of muscle and adipose tissue appear to be secreted by cachexia-inducing human tumors and may play an active role in the process of tissue degeneration. Pharmacologic intervention using antagonists to cachexia factors may be capable of reversing the wasting process.

Glucose-induced thermogenesis in patients with small cell lung carcinoma. Before and after inhibition of tumour growth by chemotherapy

Seven weight-losing patients with histologically verified small cell lung carcinoma were given an oral glucose load of 75 g before and at least 3 weeks after the end of chemotherapy to examine the effect of glucose on whole body and skeletal muscle thermogenesis before and after reduction of tumour. Whole body energy expenditure was measured by the open circuit ventilated hood system. Forearm blood flow was measured by venous-occlusion strain-gauge plethysmography. The uptake of oxygen in skeletal muscle was calculated as the product of the forearm blood flow and the difference in a-v oxygen concentration. Whole body resting energy expenditure (REE) did not increase, it was 4.4 +/- 0.3 kJ min-1 (mean +/- SE) before chemotherapy and 4.4 +/- 0.2 kJ min-1 after chemotherapy. The glucose-induced thermogenesis in the 180 min following the glucose load was 93.6 +/- 9.9 kJ 180 min-1 before chemotherapy. This is significantly increased compared to that found in a healthy control group (74.7 +/- 4.8 kJ 180 min-1, P < 0.02). The glucose-induced thermogenesis was significantly reduced to 47.7 +/- 10.2 kJ 180 min-1 (P < 0.05) after chemotherapy. The oxygen uptake in resting skeletal muscles was 6.9 +/- 0.3 mumol 100 g-1 min-1 before chemotherapy and 7.0 +/- 0.7 mumol 100 g-1 min-1 after chemotherapy. This did not increase during the first 90 min following the glucose load in either investigations. In the period 90-180 min following the glucose load, the oxygen uptake was significantly increased before chemotherapy as compared to after chemotherapy, which suggests that the reduced whole body thermogenesis after chemotherapy in part was due to reduced skeletal muscle thermogenesis.

Serum tumour necrosis factor alpha and insulin resistance in gastrointestinal cancer

Cancer cachexia may be mediated by endogenous peptides such as tumour necrosis factor alpha (TNF-alpha). Insulin resistance occurs in these patients, and is also seen experimentally with TNF-alpha administration. In this study, insulin sensitivity and energy metabolism were measured in 11 patients with gastrointestinal cancer and ten controls, using the euglycaemic glucose clamp and indirect calorimetry. Patients with cancer were significantly more insulin resistant than controls (P < 0.01) and in such patients insulin resistance correlated with serum TNF-alpha level (rs = 0.74, P < 0.01). Fasting insulin levels also correlated inversely with insulin sensitivity (rs = -0.62, P = 0.003). These results suggest a possible association between endogenous TNF-alpha production and insulin resistance in patients with gastrointestinal cancer.

Resting energy expenditure in patients with non-small cell lung cancer

Resting energy expenditure (REE) was determined in 30 patients with newly detected non-small cell lung cancer. Measured values were compared with the values predicted by the Harris-Benedict (HB) formula. Mean REE was 20% higher than predicted. Sixty percent of the patients (18 patients) had an elevated REE (greater than or equal to 115%) compared with this formula. The prevalence of hypermetabolism in a group of patients with gastric and colorectal cancer was only 13% (13 of 104 patients). When corrected for fat-free mass (FFM), REE was still significantly higher (P less than 0.001) in the lung cancer group compared with the gastric and colorectal cancer group. Whereas weight loss in healthy men leads to an adaptational decrease in energy expenditure (EE), weight loss in the patients with lung cancer was accompanied by an increase in REE. Tumor stage, tumor localization, pulmonary function, or smoking behavior could not explain the observed increase in REE in patients with lung cancer. Therefore, these metabolic alterations appear to be tumor mediated.

Insulin action and metabolism in patients with head and neck cancer

Cachexia is a phenomenon commonly observed in patients with cancer, but its etiology is poorly understood. Abnormalities of insulin action and metabolism that have been hypothesized to promote cancer cachexia were investigated in this study using a computerized euglycemic clamp and modified frequently sampled intravenous glucose tolerance test (FSIGT) in a group of malnourished patients with localized head and neck cancer, and in healthy, well-nourished, age- and, sex-matched controls. Glucose disposal rates, determined by the euglycemic clamp at three different rates of insulin infusion did not differ significantly between the two groups. However, mean plasma insulin concentrations at each level of insulin infused were significantly lower in the patients with cancer than in the control subjects resulting in unexpectedly higher calculated insulin metabolic clearance rate in the patients with cancer. Peripheral insulin sensitivity calculated from the slope of glucose disposal versus plasma insulin concentration did not differ between the two groups. Results from the FSIGT demonstrated no difference in insulin sensitivity or insulin-independent glucose disappearance between the two groups. However, whole body glucose appearance was significantly elevated in the patients with cancer. Thus, increased whole body glucose utilization in the absence of insulin resistance or increased insulin-dependent glucose disposal was observed. These data are consistent with the concept of a localized tumor acting as a glucose drain in which case increased glucose appearance and increased insulin clearance would defend against hypoglycemia.

Energy balance in relation to cancer cachexia

The aim of the current study was to determine the contribution of increased resting energy expenditure (REE) and/or decreased energy intake (EI) to the development of weight loss in gastric and colorectal (GCR) and lung cancer patients. REE was measured in 22 GCR cancer patients and 17 lung cancer patients and was compared with REE values in 40 apparently healthy controls. REE in lung cancer patients expressed per kg fat free mass (REE/FFM) was significantly increased when compared to healthy controls (33.5 +/- 5.4 and 29.6 +/- 2.9 kcal, respectively; p < 0.01). GCR cancer patients had no elevated REE compared to these healthy controls. No significant differences in EI were established between the three groups. Eight GCR cancer patients reported a decrease in food intake compared to pre-disease intake, in contrast to only one lung cancer patient. Semi-starving GCR cancer patients showed a significant weight loss (8.7 +/- 8.1%), a low respiratory quoteint (RQ) (0.76 +/- 0.04) and a high beta-hydroxybutyrate level (259 +/- 192 mumol/l), but they showed no difference in REE compared to patients with a normal EI. The current study suggests that weight loss in GCR cancer patients is initiated by decreased food intake, whereas weight loss in lung cancer patients represents a combination of an increased REE and a relatively low EI.

Glucose metabolism and colorectal carcinoma

We evaluated nine patients with colorectal cancer and six control patients in a postabsorptive state in an attempt to define the effect of cancer on glucose turnover, oxidation, recycling, and resting metabolic expenditures (RME). The glucose kinetics were determined using a double-labeled [U-14C] glucose and [6-3H] glucose, and energy expenditures were measured by indirect calorimetry. In addition, we also measured the same parameters in the cancer patient group on a total parenteral nutrition (TPN)-glucose system on the fourth day before and on the fifth day after removal of tumor. In the postabsorptive state, glucose turnover and oxidation rates were similar in the cancer and control group; however, the mean glucose pool size of the cancer group was 47% larger than the control group and was statistically significant (P = .05). Glucose recycling was also two times the control group and was statistically significant (P = .05). The recycling of glucose, both preoperatively and postoperatively, continued in the face of infused glucose; however, the rate was suppressed compared with the fasting cancer group. Postabsorptive RME of the cancer group did not differ from those predicted by the Harris-Benedict equation. Following a 4-day infusion of TPN-glucose that supplied a mean of two times the patients' energy needs, the preoperative cancer group showed a mean increase in RME of 25.6% and a 31.58% increase on the fifth postoperative day of TPN-glucose, presumably due to increased lipogenesis and to a much lesser extent from the increased protein synthesis (4 g positive N balance).(ABSTRACT TRUNCATED AT 250 WORDS)