Zinc as a complementary treatment for cancer patients: a systematic review

Abstract

Zinc is a trace element that plays an important role in the immune system and cell growth. The role of zinc in cancer treatment has been discussed for some time, however without reaching an evidenced-based consensus. Therefore, we aim to critically examine and review existing evidence on the role of zinc during cancer treatment. In January 2019, a systematic search was conducted searching five electronic databases (Embase, Cochrane, PsychINFO, CINAHL and PubMed) to find studies concerning the use, effectiveness and potential harm of zinc therapy on cancer patients. Out of initial 5244 search results, 19 publications concerning 23 studies with 1230 patients were included in this systematic review. The patients treated with zinc were mainly diagnosed with head and neck cancer and underwent chemo-, radio- or concurrent radio-chemotherapy. Interventions included the intake of different amounts of zinc supplements and oral zinc rinses. Outcomes (primary endpoints) investigated were mucositis, xerostomia, dysgeusia, pain, weight, dermatitis and oral intake of nutrients. Secondary endpoints were survival data, quality of life assessments and aspects of fatigue, immune responses and toxicities of zinc. The studies were of moderate quality reporting heterogeneous results. Studies have shown a positive impact on the mucositis after radiotherapy. No protection was seen against mucositis after chemotherapy. There was a trend to reduced loss of taste, less dry mouth and oral pain after zinc substitution. No impact was seen on weight, QoL measurements, fatigue, and survival. The risk of side effects from zinc appears to be relatively small. Zinc could be useful in the prevention of oral toxicities during irradiation. It does not help in chemotherapy-induced side effects.

Managing Severe Dysgeusia and Dysosmia in Lung Cancer Patients: A Systematic Scoping Review

“…Despite multiple investigations into how zinc can impact cancer treatment toxicities, there remains a lack of evidence to form a common consensus on its role ( 42 ).…”

Counseling on Complementary Methods in the Treatment of Side Effects of Oncological Therapies: A Project of the Breast and Bowel Center Nahe at the Hospital Sankt Marienwoerth Bad Kreuznach

“…An intensive literature review was conducted to inform participants. We searched reference books 12 - 14 and PubMed 15 - 40 for information on complementary methods in oncology.…”

Polypharmacy and Malnutrition Management of Elderly Perioperative Patients with Cancer: A Systematic Review

“…A Cochrane review that examined the improvement of taste perception due to zinc supplementation in patients with idiopathic and zinc-deficient taste disorders found very low-quality evidence that zinc supplementation improves taste perception (relative risk: 1.42, 95% confidence interval: 1.09-1.84; 292 participants, two trials) [32]. Zinc could be useful in the prevention of oral toxicities during irradiation; however, it does not alleviate chemotherapy-induced side effects [33]. Accordingly, several studies have proposed that zinc does not have a positive effect on patient weight or food intake [32].…”