Ascorbic acid in cancer management – time for a second look

Abstract

Introduction and aim. Over the past decades, the hypotheses that ascorbic acid (AA) can play a role as an anti-neoplastic therapy have generated many conflicting reports. Despite the controversies, mounting evidence has shown that AA has the potential to play a role as an anti-neoplastic agent. Recent studies have unraveled its pharmacokinetics and various mechanism of action on cancer cells. This has spawned different preclinical studies with reports of good activities against various cancers. Material and methods. A review of the literature regarding ascorbic acid in the management of cancer was performed using the PubMed database. The research was limited to abstracts and available full-text articles. Analysis of the literature. Clinical trials have also demonstrated its safety and tolerability across different dosages. AA has been noted as a multitargeting agent that acts as a pro-oxidative cytotoxic agent, anti-cancer epigenetic regulator and immune modulator. AA has also been shown act synergistically with standard chemotherapy regimens in different cancers. Despite its potentials, phase III clinical trials are seriously lacking. The recent phase III VITALITY study shows that AA may play a role as an adjunct targeted therapy for ras-mutated cancers. Therefore, there is need to for more standardized clinical trials to help identify cancer subtypes and AA combination regimens that can show the most benefits. In this review, the pleiotropic mechanism of action of AA was explored as well as various preclinical and clinical studies in cancer therapy. In addition, recommendations were also made for effective strategies towards an AA and standard cancer regimens in treatment as well as future directions. Ascorbic acid has been shown to induce cell death in various cancer types through different mechanisms of action. Several clinical trials and case reports have shown its efficacy in combination chemotherapy, and the pharmacological route of action can be either intravenous or oral. However, it can impair the actions of some drugs when given in combination. Also, dosage should be determined for maximal pharmacologic action. Conclusion. Ascorbic acid has the potential to provide safe and cost-effective antineoplastic treatment option especially in combination therapy. Its potential needs to be further investigated through clinical trials.