Prophylaxis with oral zinc sulfate against radiation-induced oropharyngeal mucositis in patients with head and neck cancer: Protocol for a meta-analysis of randomized controlled trials

Review Article on Molecular Basis of Zinc and Copper Interactions in Cancer Physiology

Various clinical manifestations associated with measurable abnormalities of Zn and Cu in serum and tissue were determined in Cancer-Patients (CP), and therefore, these two metals are drawing more and more attention presently than ever before. Cancer is a disease of uncontrolled-abnormal-cell-division with invasion-potential which was exhibited to occur due to dys-regulation/dys-homeostasis of fundamental-biological-pathways (FBP) including antioxidant-enzyme-defense-system, anti-inflammatory and immune-systems, and DNA-damage-repair-system in the human-body resulting in generation of chronic-oxidative-stress induced DNA-damage and gene-mutations, inflammation and compromised immune-system, tumor-induced increased angiogenesis, and inhibition of apoptosis processes. Zn and Cu were recognized to be the most crucial components of FBP and imbalance in Zn/Cu ratios in CP asserted to generate chronic toxicity in human body through various mechanisms including increased chronic oxidative stress linked compromised DNA integrity and gene mutations due to malfunctioning of DNA damage repair enzymes; increased angiogenesis process due to Zn- and Cu-binding proteins metallothionein and ceruloplasmin-induced enhanced expression of tumor growth factors; and elevation in inflammatory response which was further shown to down/upregulate gene expression of multiple Zn transporter proteins leading to dys-homeostasis of intracellular Zn concentrations, and it was determined to disturb the equilibrium between cell growth and division, proliferation, differentiation, and apoptosis processes which lead to cancer progression. Moreover, Zn was reported to affect matrix metalloproteinase activity and influence immune system cells to respond differently to different cytokines and enhance immune-suppressive effects accelerating the angiogenesis, invasion, and metastasis potential in cancer. Further, the most significant use of serum Cu/Zn ratio was recommended in clinical diagnosis, prognosis, tumor stage, patient survival, and cancer follow-up studies which need further investigations to elucidate and explore their roles in cancer physiology for clinical perspective.

Study of Serum Zinc and Copper Levels and Tumor Pathology: A Pilot Study in People Affected with Head and Neck Cancers

This study aimed to determine understanding the role of serum copper, zinc and copper/zinc ratio with tumor staging in people newly diagnosed to be affected with Head and Neck cancer and by comparing with age matched health individuals devoid of any orodental maladies. The study included patients confirmed to be affected with HN cancer with histological diagnosis of Head and Neck cancer (60) and age matched healthy volunteers (N = 23). The demographic details like age, domicile, menopausal status and pathological details (like tumor stage, number of lymph node involvement, tumor size) were collected from the patient's hospital data file. The serum levels of zinc and copper assayed as per standard procedures and the zinc/copper was calculated for the cancer patients and controls. The data were subjected to unpaired "t" test and ANOVA with Bonferroni's multiple comparisons. The association between zinc and copper levels with pathological details between the variables was ascertained using the Pearson correlation coefficient(r). A statistical value of p < 0.05 was considered to be significant in agreeance to the accepted norms. Results: This result of the study indicates that when compared to the healthy individuals, the serum levels of copper, and zinc, and copper/zinc ratio were high in patients with H&N cancer. Also when compared with controls, the levels of zinc decreased, while that of copper and copper/zinc ratio increased in people affected with H&N cancer (p = 0.017 to 0.0001) and with the stage of the tumor (p = 0.03 to 0.001). The results of the study suggest that levels of serum zinc were significantly lower and that of copper higher in H&N cancer patients than that in controls and also that it was dependent on the tumor stage. When analyzed cumulatively the results hint that zinc and copper, due to their role in free radical generation and prevention have an important role in cancer progression and possible prevention by judicious intervention.

Nutritional supplements in the management of oral mucositis in patients with head and neck cancer: Narrative literary review

BACKGROUND AND AIMS

Oral mucositis is the most common side effect in response to anticancer therapies in the head and neck region. It has a debilitating potential for the health of affected individuals, negatively interfering with nutritional status and quality of life. Due to the great complexity of its pathogenicity, different forms of interventions for prevention and treatment are being studied, including nutritional supplements with vitamin E, zinc and glutamine. This study aimed to review the literature on the influence of nutrients, in supplement form, for prevention and/or treatment of mucositis in patients with head and neck cancer.

METHODS

A survey of studies related to the definition, treatment and prevention of mucositis with nutrients was carried out between January 2018 and July 2019, using the Pubmed, Cochrane Library and Scielo databases. In the end, 61 relevant scientific publications were selected between the years 2004 and 2019.

RESULTS

Nutrients such as vitamin E, glutamine and zinc are forms of supplementation that have positive effects on the manifestation and severity of oral mucositis due to their antioxidant and immunomodulatory properties. However, some studies reveal that antioxidant properties may reduce the effectiveness of antineoplastic therapy.

CONCLUSIONS

This study suggests the effectiveness of vitamin E, zinc and glutamine in preventing and treating oral mucositis. However, the importance of new clinical researches to clarify possible doubts is highlighted, as well as the creation of a protocol that includes the dose, route and time of administration, for greater safety in use.

Effect of zinc on oropharyngeal mucositis in children with acute leukemia undergoing chemotherapy

Background

Oropharyngeal mucositis (OM) is one of the main side-effects of oncological therapy. There is no treatment to prevent its occurrence, but some zinc-based therapies have been proven to help in decreasing its intensity. The objective of this study was to determine the effect of zinc in OM in children with acute leukemia in the early stages of oncological treatment.

Material and Methods

This quasi-experimental study evaluated OM in 2 groups (control group: conventional hospital management, and experimental group: administration of 50 mg of zinc gluconate daily plus conventional hospital management). OM severity was recorded at a two-month follow-up.

Results

Forty-nine patients (26 in the control group and 23 in the experimental group) were included. The mean age of the patients was 11.1 ± 2.7 years; 65.3% had a diagnosis of pre-B acute lymphoblastic leukemia. The incidences of OM in the control group and the experimental group were 46.2% and 26.1%, respectively, but the difference was not significant. Based on a negative binomial regression model, females had, on average, 1.5 more days with OM (p = 0.002), and patients assigned to the experimental group had, on average, 2 less days with OM than the control group (p = 0.001). The pain score was higher in the control group (p = 0.0009), as was the mean score on the WHO scale (p = 0.0012).

Conclusions

Zinc facilitated a reduction in the severity and duration of OM; further studies focusing on children are needed to confirm the effects of this trace element.

Key words:Oropharyngeal, mucositis, zinc, chemotherapy, children, leukemia.

Prophylaxis With Oral Zinc Sulfate Against Radiation Induced Oral Mucositis in Patients With Head and Neck Cancers: A Systematic Review and Meta-Analysis of Four Randomized Controlled Trials

Background: Oral mucositis is an inevitable and distressing adverse event patients, who were treated with irradiation for head and neck cancer, face. Although several studies have investigated the potential of oral zinc sulfate in preventing radiation-induced oral mucositis in patients with head and neck cancers, conclusive results have not yet been found.

Objective: The aim of the present study is to determine whether oral zinc sulfate is effective in preventing radiation-induced oral mucositis, in patients with head and neck cancers.

Methods: We electronically searched all potential citations in PubMed, EMBASE, Cochrane Central Register of Controlled Trials (CENTRAL) and EBSCO from their inception to December 2018. After the search and checked literatures, extracted data and appraised risk of bias, RevMan software version 5.3 was used to perform meta-analysis.

Results: Four randomized controlled trials (RCTs) involving 162 patients were included. A meta-analysis showed that zinc sulfate did not decrease the incidence (RR [relative risk], 0.97; 95% CI [confidence interval], 0.74–1.28), and did not relieve the moderate and severe grade of radiation induced oral mucositis (moderate and severe oral mucositis: RR, 0.84; 95% CI, 0.14–4.87; severe oral mucositis: RR, 0.43; 95% CI, 0.00–38.98). A qualitative analysis suggested that zinc sulfate was associated with the onset of oral mucositis.

Conclusions: Based on limited evidence, zinc sulfate may not have the benefit of prophylaxis against radiation-induced oral mucositis, in patients with head and neck cancers. However, further RCTs with larger sample sizes and more rigorous methodologies are needed to enhance the evidence of these results.