RT Journal Article
SR Electronic
T1 Intravenously administered vitamin C as cancer therapy: three cases
JF Canadian Medical Association Journal
JO CMAJ
FD Canadian Medical Association
SP 937
OP 942
DO 10.1503/cmaj.050346
VO 174
IS 7
A1 Sebastian J. Padayatty
A1 Hugh D. Riordan
A1 Stephen M. Hewitt
A1 Arie Katz
A1 L. John Hoffer
A1 Mark Levine
YR 2006
UL http://www.cmaj.ca/content/174/7/937.abstract
AB Early clinical studies showed that high-dose vitamin C, given by intravenous and oral routes, may improve symptoms and prolong life in patients with terminal cancer. Double-blind placebo-controlled studies of oral vitamin C therapy showed no benefit. Recent evidence shows that oral administration of the maximum tolerated dose of vitamin C (18 g/d) produces peak plasma concentrations of only 220 μmol/L, whereas intravenous administration of the same dose produces plasma concentrations about 25-fold higher. Larger doses (50–100 g) given intravenously may result in plasma concentrations of about 14 000 μmol/L. At concentrations above 1000 μmol/L, vitamin C is toxic to some cancer cells but not to normal cells in vitro. We found 3 well-documented cases of advanced cancers, confirmed by histopathologic review, where patients had unexpectedly long survival times after receiving high-dose intravenous vitamin C therapy. We examined clinical details of each case in accordance with National Cancer Institute (NCI) Best Case Series guidelines. Tumour pathology was verified by pathologists at the NCI who were unaware of diagnosis or treatment. In light of recent clinical pharmacokinetic findings and in vitro evidence of anti-tumour mechanisms, these case reports indicate that the role of high-dose intravenous vitamin C therapy in cancer treatment should be reassessed.