Key Takeaway
Systematic review of 37 studies found IV vitamin C in cancer patients appears safe and may improve quality of life and reduce chemotherapy side effects, but high-quality efficacy evidence remains limited.
Summary
Comprehensive systematic review examining the safety, effectiveness, and pharmacokinetics of intravenous vitamin C (IVC) as a therapy in cancer populations. The review searched MEDLINE, EMBASE, Cochrane Library, CINAHL, and AMED databases from inception through April 2013.
Of 897 identified records, 39 reports covering 37 studies met inclusion criteria, including 2 RCTs, 15 uncontrolled trials, 6 observational studies, and 14 case reports. IVC dosing ranged from 1 to over 200 grams per infusion, typically administered 2-3 times weekly.
The review found that IVC does not appear to increase toxicity or interfere with antitumor effects of standard chemotherapy regimens such as gemcitabine/erlotinib or paclitaxel/carboplatin. IVC appeared beneficial for reducing chemotherapy-related symptoms including fatigue, nausea, insomnia, constipation, and depression. Case reports documented instances of tumor regression and extended disease-free survival, though the authors emphasized that the existing evidence is preliminary and cannot be considered conclusive.
Methods
- Systematic review of human interventional and observational studies
- Searched MEDLINE, EMBASE, Cochrane Library, CINAHL, AMED from inception to April 2013
- 37 studies included (2 RCTs, 15 uncontrolled trials, 6 observational, 14 case reports)
- Assessed safety, effectiveness, and pharmacokinetics of IVC in cancer patients
Key Results
- IVC does not appear to increase toxicity or interfere with chemotherapy
- Quality of life improvements: reduced fatigue, nausea, insomnia, constipation, depression
- Case reports of tumor regression and disease-free survival
- IVC doses ranged from 1 to 200+ grams per infusion, 2-3 times weekly
- Favorable safety profile across included studies
Limitations
- Very limited high-quality clinical evidence (only 2 RCTs)
- Predominantly case reports and uncontrolled trials
- Heterogeneous cancer types, IVC doses, and outcome measures
- Cannot draw conclusive efficacy claims from existing evidence
- Publication bias likely favors positive case reports