Correlating symptoms and their changes with survival in patients with brain metastases

Metabolic underpinnings of cancer-related fatigue

Cancer-related fatigue (CRF) is one of the most prevalent and detrimental complications of cancer. Emerging evidence suggests that obesity and insulin resistance are associated with CRF occurrence and severity in cancer patients and survivors. In this narrative review, we analyzed recent studies including both preclinical and clinical research on the relationship between obesity and/or insulin resistance and CRF. We also describe potential mechanisms for these relationships, though with the caveat that because the mechanisms underlying CRF are incompletely understood, the mechanisms mediating the association between obesity/insulin resistance and CRF are similarly incompletely delineated. The data suggest that, in addition to their effects to worsen CRF by directly promoting tumor growth and metastasis, obesity and insulin resistance may also contribute to CRF by inducing chronic inflammation, neuroendocrinological disturbance, and metabolic alterations. Furthermore, studies suggest that patients with obesity and insulin resistance experience more cancer-induced pain and are at more risk of emotional and behavioral disruptions correlated with CRF. However, other studies implied a potentially paradoxical impact of obesity and insulin resistance to reduce CRF symptoms. Despite the need for further investigation utilizing interventions to directly elucidate the mechanisms of cancer-related fatigue, current evidence demonstrates a correlation between obesity and/or insulin resistance and CRF, and suggests potential therapeutics for CRF by targeting obesity and/or obesity-related mediators.

Feasibility of automated planning for whole-brain radiation therapy using deep learning

PURPOSE

The purpose of this study was to develop automated planning for whole-brain radiation therapy (WBRT) using a U-net-based deep-learning model for predicting the multileaf collimator (MLC) shape bypassing the contouring processes.

METHODS

A dataset of 55 cases, including 40 training sets, five validation sets, and 10 test sets, was used to predict the static MLC shape. The digitally reconstructed radiograph (DRR) reconstructed from planning CT images as an input layer and the MLC shape as an output layer are connected one-to-one via the U-net modeling. The Dice similarity coefficient (DSC) was used as the loss function in the training and ninefold cross-validation. Dose-volume-histogram (DVH) curves were constructed for assessing the automatic MLC shaping performance. Deep-learning (DL) and manually optimized (MO) approaches were compared based on the DVH curves and dose distributions.

RESULTS

The ninefold cross-validation ensemble test results were consistent with DSC values of 94.6 ± 0.4 and 94.7 ± 0.9 in training and validation learnings, respectively. The dose coverages of 95% target volume were (98.0 ± 0.7)% and (98.3 ± 0.8)%, and the maximum doses for the lens as critical organ-at-risk were 2.9 Gy and 3.9 Gy for DL and MO, respectively. The DL technique shows the consistent results in terms of the DVH parameter except for MLC shaping prediction for dose saving of small organs such as lens.

CONCLUSIONS

Comparable with the MO plan result, the WBRT plan quality obtained using the DL approach is clinically acceptable. Moreover, the DL approach enables WBRT auto-planning without the time-consuming manual MLC shaping and target contouring.

Whole-brain irradiation differentially modifies neurotransmitters levels and receptors in the hypothalamus and the prefrontal cortex

BACKGROUND

Whole-brain radiotherapy is a primary treatment for brain tumors and brain metastasis, but it also induces long-term undesired effects. Since cognitive impairment can occur, research on the etiology of secondary effects has focused on the hippocampus. Often overlooked, the hypothalamus controls critical homeostatic functions, some of which are also susceptible after whole-brain radiotherapy. Therefore, using whole-brain irradiation (WBI) in a rat model, we measured neurotransmitters and receptors in the hypothalamus. The prefrontal cortex and brainstem were also analyzed since they are highly connected to the hypothalamus and its regulatory processes.

METHODS

Male Wistar rats were exposed to WBI with 11 Gy (Biologically Effective Dose = 72 Gy). After 1 month, we evaluated changes in gamma-aminobutyric acid (GABA), glycine, taurine, aspartate, glutamate, and glutamine in the hypothalamus, prefrontal cortex, and brainstem according to an HPLC method. Ratios of Glutamate/GABA and Glutamine/Glutamate were calculated. Through Western Blott analysis, we measured the expression of GABAa and GABAb receptors, and NR1 and NR2A subunits of NMDA receptors. Changes were analyzed comparing results with sham controls using the non-parametric Mann-Whitney U test (p < 0.05).

RESULTS

WBI with 11 Gy induced significantly lower levels of GABA, glycine, taurine, aspartate, and GABAa receptor in the hypothalamus. Also, in the hypothalamus, a higher Glutamate/GABA ratio was found after irradiation. In the prefrontal cortex, WBI induced significant increases of glutamine and glutamate, Glutamine/Glutamate ratio, and increased expression of both GABAa receptor and NMDA receptor NR1 subunit. The brainstem showed no statistically significant changes after irradiation.

CONCLUSION

Our findings confirm that WBI can affect rat brain regions differently and opens new avenues for study. After 1 month, WBI decreases inhibitory neurotransmitters and receptors in the hypothalamus and, conversely, increases excitatory neurotransmitters and receptors in the prefrontal cortex. Increments in Glutamate/GABA in the hypothalamus and Glutamine/Glutamate in the frontal cortex indicate a neurochemical imbalance. Found changes could be related to several reported radiotherapy secondary effects, suggesting new prospects for therapeutic targets.

Pseudoprogression of Melanoma Brain Metastases

PURPOSE OF REVIEW

Immune checkpoint inhibitors are increasingly being used to treat melanoma brain metastases. One potential complication of immune checkpoint inhibitors is a phenomenon called pseudoprogression, in which a tumor transiently increases in size due to lymphocyte infiltration. This article reviews the characteristics of pseudoprogression and their clinical implications.

RECENT FINDINGS

Pseudoprogression can be challenging to differentiate from true progression noted clinically or radiographically, thereby complicating management decisions and potentially confusing patients and their families. The transient tumor enlargement can also cause symptoms that mimic true tumor progression. Because the use of immunotherapy on melanoma brain metastases is a relatively new treatment paradigm, there is limited evidence to guide clinical decision-making and prognostication related to pseudoprogression.

Depression and survival of glioma patients: A systematic review and meta-analysis

INTRODUCTION

There is currently a lack of a well-formed consensus regarding the effects of depression on the survival of glioma patients. A more thorough understanding of such effects may better highlight the importance of recognizing depressive symptoms in this patient population and guide treatment plans in the future.

OBJECTIVE

The aim of this meta-analysis was to study the effect of depression on glioma patients' survival.

METHODS

A meta-analysis was conducted according to the PRISMA guidelines. PubMed, Embase, and Cochrane databases were searched for studies that reported depression and survival among glioma patients through 11/06/2016. Both random-effects (RE) and fixed-effect (FE) models were used to compare survival outcomes in glioma patients with and without depression.

RESULTS

Out of 619 identified articles, six were selected for the meta-analysis. Using RE model, the various measures for survival outcomes displayed worsened outcomes for both high and low-grade glioma patients with depression compared to those without depression. For binary survival outcomes, the overall pooled risk ratio for survival was 0.70 (95% CI: 0.47, 1.04; 6 studies; I² = 54.9%, P-heterogeneity = 0.05) for high grade gliomas (HGG) and 0.28 (95% CI: 0.04, 1.78; I² = 0%, P-heterogeneity = 1.00; one study) for low grade gliomas (LGG) was. A sub-group analysis in the HGG group by depression timing (pre- versus post-operative) revealed no differences between depression and survival outcomes (P-interaction = 0.47). For continuous survival outcomes, no statistically significant difference was found among the high and low-grade glioma groups (P-interaction = 0.31). The standardized mean difference (SMD) in survival outcomes was -0.56 months (95%CI: -1.13, 0.02; 4 studies, I² = 89.4%, P-heterogeneity < 0.01) for HGG and -1.69 months (95%CI: -3.26, -0.13; one study; I² = 0%, P-heterogeneity = 1.00) for LGG. In patients with HGG, the pooled HR of death also showed a borderline significant increased risk of death among depressive patients (HR 1.42, 95% CI: 1.00, 2.01). Results using the FE model were not materially different.

CONCLUSIONS

Depression was associated with significantly worsened survival regardless of time of diagnosis, especially among patients with high-grade glioma.

RON tyrosine kinase mutations in brain metastases from lung cancer

Brain metastases originate from cancer cells that have spread through the bloodstream and reached the brain from primary tumours in other organs. Metastatic masses are among the most common intracranial neoplasms, occurring in ∼25% of cancer patients. Most brain metastases derive from lung cancers (40–50% of cases), breast cancers (10–16%), melanoma (5–20%), kidney and ovarian cancers (5–10%) and more rarely colorectal cancers. Sometimes (5–10%) no primary site is detectable [1]. The onset of brain lesions from primary solid cancers is associated with poor prognosis with a median survival of 4–5 months [2]. Molecular mechanisms regulating metastatic spreading to the brain are largely unknown. RON (Recepteur d'Origine Nantais), also known as macrophage-stimulating receptor-1 (MSTR1) or stem cell derived tyrosine kinase (STK) in mice, belongs to the family of tyrosine kinase receptors of which MET is the prototype. It has been shown that RON regulates cellular proliferation, adhesion, motility and protection from apoptosis, all events resulting in the invasive growth genetic programme [3], which occurs in specific physiological conditions (i.e. embryonic development) and, when aberrantly regulated, contributes to tumour onset, progression and, above all, metastatic dissemination.

RON mutations might identify actionable targets in highly aggressive lung tumourshttp://ow.ly/RTUp30hSBX6

Assessing pathophysiology of cancer anorexia

PURPOSE OF REVIEW

Cancer anorexia is a negative prognostic factor and is broadly defined as the loss of the interest in food. However, multiple clinical domains contribute to the phenotype of cancer anorexia. The characterization of the clinical and molecular pathophysiology of cancer anorexia may enhance the efficacy of preventive and therapeutic strategies.

RECENT FINDINGS

Clinical trials showed that cancer anorexia should be considered as an umbrella encompassing different signs and symptoms contributing to appetite disruption in cancer patients. Loss of appetite, early satiety, changes in taste and smell are determinants of cancer anorexia, whose presence should be assessed in cancer patients. Interestingly, neuronal correlates of cancer anorexia-related symptoms have been revealed by brain imaging techniques.

SUMMARY

The pathophysiology of cancer anorexia is complex and involves different domains influencing eating behavior. Limiting the assessment of cancer anorexia to questions investigating changes in appetite may impede correct identification of the targets to address.