Investigating the utility of serum cytokine measurements in a multi-institutional cancer anorexia/weight loss trial

Molecular pathways leading to loss of skeletal muscle mass in cancer cachexia--can findings from animal models be translated to humans?

Background

Cachexia is a multi-factorial, systemic syndrome that especially affects patients with cancer of the gastrointestinal tract, and leads to reduced treatment response, survival and quality of life. The most important clinical feature of cachexia is the excessive wasting of skeletal muscle mass. Currently, an effective treatment is still lacking and the search for therapeutic targets continues. Even though a substantial number of animal studies have contributed to a better understanding of the underlying mechanisms of the loss of skeletal muscle mass, subsequent clinical trials of potential new drugs have not yet yielded any effective treatment for cancer cachexia. Therefore, we questioned to which degree findings from animal studies can be translated to humans in clinical practice and research.

Discussion

A substantial amount of animal studies on the molecular mechanisms of muscle wasting in cancer cachexia has been conducted in recent years. This extensive review of the literature showed that most of their observations could not be consistently reproduced in studies on human skeletal muscle samples. However, studies on human material are scarce and limited in patient numbers and homogeneity. Therefore, their results have to be interpreted critically.

Summary

More research is needed on human tissue samples to clarify the signaling pathways that lead to skeletal muscle loss, and to confirm pre-selected drug targets from animal models in clinical trials. In addition, improved diagnostic tools and standardized clinical criteria for cancer cachexia are needed to conduct standardized, randomized controlled trials of potential drug candidates in the future.

The cancer anorexia/weight loss syndrome: exploring associations with single nucleotide polymorphisms (SNPs) of inflammatory cytokines in patients with non-small cell lung cancer

OBJECTIVE

The cancer anorexia/weight loss syndrome commonly occurs in patients with non-small cell lung cancer (NSCLC) and is characterized by loss of weight and appetite as well as diminished survival. The current study explored whether any of 22 single nucleotide polymorphisms (SNPs) of certain previously implicated inflammatory cytokines (interleukin-1 beta, interleukin-1RN, interleukin-6, and tumor necrosis factor) are associated with this syndrome.

PATIENTS AND METHODS

All NSCLC patients who had been enrolled in the Mayo Clinic Lung Cancer Cohort, had completed a health-related questionnaire approximately 6 months after enrollment, and had blood drawn were included in this study, thus yielding a sample size of 471 patients.

RESULTS

Sixty-six (14%) patients manifested weight loss shortly after diagnosis, and 152 (32%) reported appetite loss. Only tumor necrosis factor alpha rs800629 was associated with anorexia (odds ratio: 0.46; 95% confidence interval: 0.29, 0.72; p < 0.001); patients who were heterozygous and minor homozygous were less likely to suffer anorexia. Otherwise, there were no statistically significant associations between any of the other 21 SNPs and weight loss and/or anorexia. In univariate analyses, weight loss, anorexia, more advanced cancer stage, and interleukin-1 beta rs1143627 were associated with a worse survival, and interleukin-6 rs2069835 was associated with better survival. However, in multivariate analyses, cancer stage and patient age were the only statistically significant predictors of worse survival.

CONCLUSION

No specific SNP was associated with all aspects of the cancer anorexia/weight loss syndrome, but rs800629 may merit further study in cancer-associated anorexia.

A randomized, double-blind, placebo-controlled trial of a beta-hydroxyl beta-methyl butyrate, glutamine, and arginine mixture for the treatment of cancer cachexia (RTOG 0122)

PURPOSE

Cancer cachexia is a common problem among advanced cancer patients. A mixture of beta-hydroxyl beta-methyl butyrate, glutamine, and arginine (HMB/Arg/Gln) previously showed activity for increasing lean body mass (LBM) among patients with cancer cachexia. Therefore a phase III trial was implemented to confirm this activity.

MATERIALS AND METHODS

Four hundred seventy-two advanced cancer patients with between 2% and 10% weight loss were randomized to a mixture of beta-hydroxyl beta-methyl butyrate, glutamine, and arginine or an isonitrogenous, isocaloric control mixture taken twice a day for 8 weeks. Lean body mass was estimated by bioimpedance and skin-fold measurements. Body plethysmography was used when available. Weight, the Schwartz Fatigue Scale, and the Spitzer Quality of Life Scale were also measured.

RESULTS

Only 37% of the patients completed protocol treatment. The majority of the patient loss was because of patient preference (45% of enrolled patients). However, loss of power was not an issue because of the planned large target sample size. Based on an intention to treat analysis, there was no statistically significant difference in the 8-week lean body mass between the two arms. The secondary endpoints were also not significantly different between the arms. Based on the results of the area under the curve (AUC) analysis, patients receiving HMB/Arg/Gln had a strong trend higher LBM throughout the study as measured by both bioimpedance (p = 0.08) and skin-fold measurements (p = 0.08). Among the subset of patients receiving concurrent chemotherapy, there were again no significant differences in the endpoints. The secondary endpoints were also not significantly different between the arms.

CONCLUSION

This trial was unable to adequately test the ability of beta-hydroxy beta-methylbutyrate, glutamine, and arginine to reverse or prevent lean body mass wasting among cancer patients. Possible contributing factors beyond the efficacy of the intervention were the inability of patients to complete an 8-week course of treatment and return in a timely fashion for follow-up assessment, and because the patients may have only had weight loss possible not related to cachexia, but other causes of weight loss, such as decreased appetite. However, there was a strong trend towards an increased body mass among patients taking the Juven compound using the secondary endpoint of AUC.

The cancer anorexia/weight loss syndrome: therapeutic challenges

The cancer anorexia/weight loss syndrome is characterized by loss of weight, loss of appetite, overall decline in quality of life, and shortened survival in patients with advanced incurable cancer. It is highly prevalent. To date, treatment options that have been firmly established with good scientific evidence are limited to progestational agents and corticosteroids, both of which have been demonstrated to improve appetite but have otherwise failed to have a favorable impact on some of the other aspects of this syndrome. As the mechanisms behind this syndrome are further elucidated, more effective therapeutic strategies will likely emerge.