Anorexia, serum zinc, and immunologic response in small cell lung cancer patients receiving chemotherapy and prophylactic cranial radiotherapy

Metallic taste prevalence in patients treated for cancer: a systematic literature review and meta-analysis

BACKGROUND

Metallic taste (MT) is a taste abnormality often reported by cancer patients. The aim of this systematic review was to exhaustively report MT incidences in cancer patients and to evaluate the risk of bias in the pertinent studies in accordance with a meta-analysis approach.

METHODS

The research objective was to determine the prevalence of MT in patients treated for cancer. A literature search was conducted using PubMed, Web of Science, and Embase. The authors each screened articles and evaluated the eligibility and individual risk of bias for each article. Then, all of the results were compared. A meta-analysis was conducted on studies that specifically focused on MT evaluation.

RESULTS

Very few articles have been published on the incidence of MT among taste and smell abnormalities in cancerology (22 of 1674, 1.3%), and the quality of the reports on MT was often low. The most common bias was the methodology used for MT evaluation. Pooling the results of the 22 studies led to an estimated MT incidence in the cancer patient population of 29% (95% CI [0.21; 0.39]) with high and significant heterogeneity observed among the studies. A heterogeneity analysis was performed to identify the causal factors of this heterogeneity. The specific impact of MT on nutritional status (two) and quality of life (five) studies were reported, respectively, and without a specific evaluation of MT. There was no mention of oral health in any of the studies.

CONCLUSION

Although in clinical practice cancer patients often report MT, its incidence has only been reported in 22 studies, most of which have a moderate to severe risk of bias. Considering the rather high prevalence of MT, more research should be conducted in this field to better identify its causes and mechanisms.

Pathophysiology of anorexia in the cancer cachexia syndrome

Anorexia is commonly present in persons with cancer and a major component of cancer cachexia. There are multiple causes of anorexia in cancer. Peripherally, these can be due to (i) substances released from or by the tumour, e.g. pro-inflammatory cytokines, lactate, and parathormone-related peptide; (ii) tumours causing dysphagia or altering gut function; (iii) tumours altering nutrients, e.g. zinc deficiency; (iv) tumours causing hypoxia; (v) increased peripheral tryptophan leading to increased central serotonin; or (vi) alterations of release of peripheral hormones that alter feeding, e.g. peptide tyrosine tyrosine and ghrelin. Central effects include depression and pain, decreasing the desire to eat. Within the central nervous system, tumours create multiple alterations in neurotransmitters, neuropeptides, and prostaglandins that modulate feeding. Many of these neurotransmitters appear to produce their anorectic effects through the adenosine monophosphate kinase/methylmalonyl coenzyme A/fatty acid system in the hypothalamus. Dynamin is a guanosine triphosphatase that is responsible for internalization of melanocortin 4 receptors and prostaglandin receptors. Dynamin is up-regulated in a mouse model of cancer anorexia. A number of drugs, e.g. megestrol acetate, cannabinoids, and ghrelin agonists, have been shown to have some ability to be orexigenic in cancer patients.

Systemic zinc redistribution and dyshomeostasis in cancer cachexia

Cachexia affects up to two thirds of all cancer patients and is a significant cause of morbidity and mortality. It is a complex metabolic syndrome associated with the underlying illness and characterized by loss of skeletal muscle tissue with or without loss of fat mass. Cachexia's other prominent clinical symptoms include anorexia, systemic inflammation, pediatric growth failure, and hypogonadism. The relationship between the symptoms of cancer cachexia and the underlying illness is unclear, and there is an urgent need for a better understanding of the pathophysiology of this syndrome. Normal Zn metabolism is often disrupted in cancer patients, but the possible effects of systemic Zn dyshomeostasis in cachexia have not been investigated. We propose that the acute phase response can mediate Zn redistribution and accumulation in skeletal muscle tissue and contribute to the activation of the ubiquitin-proteasome pathway that regulates protein catabolism. This chronic redistribution deprives Zn from other tissues and organs and compromises critical physiological functions in the body. The cardinal symptoms of Zn deficiency are anorexia, systemic inflammation, growth failure in children, and hypogonadism. These symptoms also prominently characterize cancer cachexia suggesting that the role of systemic Zn dyshomeostasis in cachexia should be investigated.

Quality of life, taste, olfactory and oral function following high-dose chemotherapy and allogeneic hematopoietic cell transplantation

Multiple oral complaints develop following high-dose chemo/radiotherapy and hematopoietic cell transplantation (HCT) which can influence quality of life. The purpose of this investigation was to assess quality of life, oral function, taste and smell in a cohort of patients following HCT. A general quality of life survey (the European Organization for Research and Treatment of Cancer (EORTC)) Quality of Life (QOL) questionnaire (QLQ-C30), with an added oral symptom and function scale and assessment of taste and smell was administered to a consecutive series of patients at day 90-100 post HCT. General QOL was impacted by fatigue, affecting physical, social emotional and cognitive function. While oral function scales appeared to be little affected at day 90-100 post HCT, abnormalities of taste were reported. Reports of changes in taste and smell appeared to parallel each other and changes remained at the time of the survey post-HCT. Change in taste appeared to be closely associated with dry mouth. Patients appeared to have difficulty in differentiating sour and bitter, which had been more affected than salt and sweet taste. Females appeared to report greater changes in taste than males. Increased smell sensitivity and taste change resulted in changes in food preparation in some cases, as did reported increase in sensitivity to sour and bitter taste. Acute complications are well known to affect QOL during the early period following HCT, but little assessment of long-term changes in oral QOL and taste has been conducted following transplant. The EORTC QLQ C-30 questionnaire with the oral addendum provides a measure of the quality of life and oral function, and may provide useful outcome measures for assessment of oral care prevention and management in HCT patients.

Acute-phase reactants and plasma trace element concentrations in non-small cell lung cancer patients and controls

This study examined the effect of an acute-phase response on plasma trace element concentrations of non-small cell lung cancer (NSCLC) patients. In normal subjects (n = 13) and NSCLC patients (n = 22), fasting concentrations of albumin, C-reactive protein, the trace elements iron, zinc, copper, and selenium, and their associated proteins transferrin, albumin, ceruloplasmin, and glutathione peroxidase were measured. The NSCLC patients were subdivided into two equal groups depending on whether they had a C-reactive protein concentration < 35 mg/l (Group 1) or > 35 mg/l (Group 2). Circulating zinc, iron, and transferrin concentrations were significantly lower in NSCLC Group 1 than in the control group (p < 0.05). Circulating concentrations of iron, zinc, and the binding proteins transferrin and albumin were significantly lower in NSCLC Group 2 than in the control group and NSCLC Group 1 (zinc not significantly different) (p < 0.01). In contrast circulating concentrations of copper and its binding protein ceruloplasmin were significantly increased in NSCLC Group 2 compared with NSCLC Group 1 and the control group (p < 0.01). Additionally, plasma selenium and glutathione peroxidase concentrations were significantly lower (p < 0.05) in NSCLC Group 2 than in NSCLC Group 1 and the control group. In the NSCLC patients there were significant negative correlations between concentrations of C-reactive protein and iron, transferrin, zinc, albumin, and selenium (p < 0.05). Furthermore, there were also significant positive correlations between C-reactive protein and copper (r = 0.788, p < 0.001) and ceruloplasmin (r = 0.831, p < 0.001) concentrations. The presence of an acute-phase response has implications for the interpretation of circulating trace element concentrations, the status of patients with NSCLC, and supplementation with trace elements in patients with NSCLC.