Re-Assessment Urged for Intravenous Vitamin C and Cancer
http://www.medpagetoday.com/HematologyOncology/OtherCancers/dh/2938
By Michael Smith, MedPage Today Staff Writer
Reviewed by Zalman S. Agus, MD; Emeritus Professor at the University of
Pennsylvania School of Medicine.
March 27, 2006
MedPage Today Action Points
- Note that despite some early studies that showed a benefit for oral and
intravenous high-dose vitamin C as a treatment for cancers, subsequent
controlled randomized trials failed to confirm the finding.
- Advise patients who ask that there is still no conclusive evidence that
high-dose intravenous vitamin C has a benefit in cancer therapy, but note that
this report suggests the approach now has some clinical and biological
plausibility.
- Note also that further study and more conclusive evidence is necessary
before high-dose vitamin C is accepted as a cancer treatment.
Review
BETHESDA, Md., March 27 - Three case reports of benefit from intravenous use
of high-dose vitamin C for cancer are being promoted here as a sign that perhaps
a reassessment of the long-discredited approach is in order.
For years high-dose vitamin C as a treatment for cancer was banished to the
category of alternative therapy, after clinical trials of oral vitamin C showed
no benefit.
But the three case studies, as well as new pharmacological evidence, suggest
that the role of high-dose vitamin C administered intravenously should be
re-assessed, according to Sebastian Padayatty, M.D., of the National Institute
of Diabetes and Digestive and Kidney Diseases here.
The three case reports increase the "clinical plausibility" that vitamin C
may have a benefit, Dr. Padayatty and colleagues wrote in the March 28 issue of
the Canadian Medical Association Journal.
It is now known, they said, that high-dose intravenous -- but not oral --
vitamin C therapy results in plasma concentrations of about 14,000 micromole per
liter. Oral doses result in plasma concentrations of at best 220 micromole per
liter.
At those concentrations in vitro, Dr. Padayatty and colleagues said, the
vitamin is toxic to some cancer cells, but not to normal cells -- a finding that
increases the "biological plausibility" of a beneficial effect.
Early studies of high-dose oral and intravenous vitamin C appeared to show a
benefit, but a randomized controlled trial of oral vitamin C failed to confirm
the finding, the researchers noted, and the idea was abandoned.
The three case studies -- of patients whose disease had a poor prognosis but
an unusually favorable outcome -- can't be regarded as conclusive, but they
"were analyzed in accordance with the National Cancer Institute's Best Case
Series process, which reports and interprets apparent responses to alternative
therapies," the researchers noted.
In the first study, a 51-year-old woman was found to have a tumor involving
her left kidney, shown after nephrectomy to be a renal cell carcinoma. CT scans
of the chest and abdomen showed no evidence of metastatic disease. However, six
months later, CT chest scans showed new small rounded and well-defined soft
tissue masses that were judged consistent with metastatic cancer. After another
seven months, multiple cannonball lesions were seen.
The patient refused conventional therapy and opted instead for high-dose
intravenous vitamin C -- 65 grams twice a week for 10 months -- as well as a
range of other alternative therapies, including thymus protein extract,
N-acetylcysteine, niacinamide, and whole thyroid extract.
Seven months after the cannonball lesions were seen, chest radiography was
normal, except for a possible pulmonary scar in the left lung.
The conclusion that the vitamin C had a beneficial effect would be
strengthened, the researchers noted, if there had been histological proof that
the cannonball lesions were actually malignant - evidence that does not exist.
However, the researchers said, the clinical characteristics and evolution of the
pulmonary lesions "make any other diagnosis unlikely."
Unfortunately, the woman -- a long-time smoker -- was diagnosed four years
later with small-cell lung cancer. She again opted for vitamin C treatment, but
the second cancer did not respond.
In the second case, a 49-year-old man was found to have a primary bladder
tumor with multiple satellite tumors. Transurethral resection of the primary and
satellite tumors was carried out. Histopathologic review at the NIH revealed a
grade 3/3 papillary transitional cell carcinoma invading the muscularis propria.
The patient declined chemotherapy and radiotherapy, opting instead for 30
grams of vitamin C twice a week for three months, followed by 30 grams once
every one to two months for four years, interspersed with periods during which
he had more frequent infusions. He also used supplements including botanical
extract, chondroitin sulfate, chromium picolinate, flax oil, glucosamine
sulfate, a-lipoic acid, Lactobacillus acidophilus, L. rhamnosus, and
selenium.
Nine years after diagnosis, the patient is in good health with no symptoms of
recurrence or metastasis, the researchers reported.
The outcome would have been unexpected, Dr. Padayatty and colleagues noted.
With only local treatment, as in this case, invasive transitional cell bladder
cancer "almost invariably develops into clinically apparent local or metastatic
disease within a short period."
In the third case, a 66-year-old woman was found to have a large left
paraspinal mass medial to the iliopsoas muscle at the L4-5 level, with evidence
of extension into the posterior paraspinal muscle and bone invasion, although
chest radiography results were normal. A biopsy was diagnostic of a diffuse
large B-cell lymphoma. Later histopathologic analysis at the NIH confirmed the
diagnosis.
The patient agreed to a five-week course of radiation, but refused
chemotherapy, opting instead for 15 grams of intravenous vitamin C twice weekly
for two months, 15 grams once to twice a week for seven months, and then 15
grams once every two to three months for about a year. The patient also used
additional products: beta-carotene, bioflavonoids, chondroitin sulfate, coenzyme
Q10, dehydroepiandrosterone, a multiple vitamin supplement, N-acetylcysteine, a
botanical supplement, and bismuth tablets.
Over the year following diagnosis and the beginning of treatment, the patient
had several occasions when axillary, cervical, sub-mandibular, or
supraclavicular lymph nodes were palpable, but at the end of that time -- and
for the 10 years since -- the patient was in normal health, with no signs of
B-cell lymphoma.
The three cases "do not provide grounds for advocating intravenous vitamin C
therapy as a cancer treatment," the researchers said. These patients received
other alternative medicine therapies and spontaneous remission of some tumors is
known to occur rarely.
On the other hand, Dr. Padayatty and colleagues said, they "increase the
clinical plausibility of the notion that vitamin C administered intravenously
might have effects on cancer under certain circumstances."
Primary source: Canadian Medical Association
Journal
Source reference:
Sebastian J. Padayatty, et al "Intravenously administered vitamin C as cancer
therapy: three cases" CMAJ 2006;174(7):937-42.
Disclaimer
The information presented in this activity is that of the authors and does not
necessarily represent the views of the University of Pennsylvania School of
Medicine, MedPage Today, and the commercial supporter. Specific medicines
discussed in this activity may not yet be approved by the FDA for the use as
indicated by the writer or reviewer. Before prescribing any medication, we
advise you to review the complete prescribing information, including
indications, contraindications, warnings, precautions, and adverse effects.
Specific patient care decisions are the responsibility of the healthcare
professional caring for the patient. Please review our Terms of Use.
© 2004-2006 MedPage Today, LLC. All Rights Reserved.
http://www.medpagetoday.com/HematologyOncology/OtherCancers/dh/2938
|
Alert Webmaster & Moderators
Already alerted! Already alerted!
|
| 
Images Description Cancer Recommended Books Cancer Homepage Rules
Home
RN by LCD
7 year
8,281
2 of 2 (100%)
Cancer Support
Important Disclaimer!
