The Vitamin E Isoform α-Tocopherol is Not Effective as a Complementary Treatment in Cancer Treatment: A Systematic Review

Abstract

The term vitamin E describes tocopherols and tocotrienols, whose chemical variations result in different biological activities including antioxidants. Neuroprotective effects of alpha-tocopherol against different toxins are assumed, therefore, it is discussed as a possible protective factor for adverse effects in cancer treatment. In July 2020, a systematic search was conducted searching five databases (Embase, Cochrane, PsychInfo, Cinahl, Medline) to find studies concerning the impact of α-tocopherol application and its potential harm on cancer patients. From 7546 search results, 22 publications referring to 20 studies with 1941 patients were included. Included patients were diagnosed with various cancer types and stages. Outcome variables were overall survival of cancer, symptom management of mucositis and chemotherapy-induced peripheral neuropathy (CIPN). The studies had different methodological qualities (mainly acceptable) and reported heterogeneous results: some reported significant improvement of mucositis and CIPN while others did not find changes concerning these endpoints. Due to heterogeneous results and methodical limitations of the included studies, a clear statement regarding the effectiveness of α-tocopherol as complementary treatment for cancer patients is not possible. Despite findings regarding reduction of oral side effects, usage of α-tocopherol during therapy must be discouraged because of potential negative influence on survival rates.

Acknowledgments

The work of SK, JD and MF was funded in parts (search of the literature, title-abstract screening) by the German Guideline “S3 Leitlinie Komplementärmedizin in der Behandlung von onkologischen PatientInnen (Registernummer 032 – 055OL)” funded by the German Cancer Aid (Fördernummer 11583) within the German Guideline Program in Oncology.

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The authors declare no conflict of interest.

Funding

The author(s) reported there is no funding associated with the work featured in this article.

Additional information

Funding

The work of SK, JD and MF was funded in parts (search of the literature, title-abstract screening) by the German Guideline “S3 Leitlinie Komplementärmedizin in der Behandlung von onkologischen PatientInnen (Registernummer 032 – 055OL)” funded by the German Cancer Aid (Fördernummer 11583) within the German Guideline Program in Oncology.