Archive for the ‘antioxidants’ Category
Antioxidants and other nutrients do not interfere with Chemotherapy or Radiation Therapy and can increase Kill and increase Survival
Category antioxidants, antioxidants, Chemotherapy, Radiation
Do Antioxidants and Chemotherapy Conflict?
Category antioxidants, antioxidants, Chemotherapy, Radiation
In September 2005, the American Cancer Society journal CA – A Cancer Journal for Clinicians published an article by Gabriella D’Andrea, MD, a medical oncologist at Memorial Sloan-Kettering Cancer Center (MSKCC), New York. The article, titled “Use of Antioxidants During Chemotherapy and Radiotherapy Should be Avoided,” is a sharp attack on the use of antioxidant supplements by cancer patients. The article received widespread public attention when it was picked up by the Wall Street Journal.
There is no doubt that the combined prestige of America’s largest private cancer center (MSKCC), wealthiest health charity (ACS), and the world’s largest daily newspaper (with an international circulation of 2.6 million), has created yet more negative publicity for antioxidants in general, and for their concurrent use with radiation and chemotherapy in particular. With every such attack, educated public opinion becomes increasingly uncertain about the benefits of these dietary components. But although the complementary and alternative medicine (CAM) movement cannot command the fire power of these giant institutions, thoughtful readers will want to probe behind the alarmist headlines and see how substantive are the charges against this use of nutritional medicine.
I have now written a full-length rebuttal of Dr. D’Andrea’s article. In preparing this monograph I consulted closely with physicians who are actively involved in research on the topic, some of whom routinely use antioxidants in their practice. Here are some of their pre-publication comments on my article:
“An excellent article that clearly brings into perspective the issues raised.”
-Kenneth A. Conklin, MD, PhD, University of California, Los Angeles
“Excellent and timely.” -Jeanne Drisko, MD, University of Kansas Medical Center
“Superb, very thorough, should convince anyone except those whose minds are closed.” -Abram Hoffer, MD, PhD, FRCP (C)
“A comprehensive rebuttal that is also an excellent review of this complex topic.” -Leanna Standish, ND, PhD, Bastyr University, Seattle
Overall, I conclude that D’Andrea’s article:
- Cites ambiguous and/or negative studies but simultaneously downplays (and frequently fails to mention) positive ones.
- Claims (correctly) that only large-scale, randomized trials provide a valid basis for therapeutic recommendations, yet uses only laboratory data to back up the claim that harm results from the use of antioxidants.
- Exaggerates the degree to which the laboratory data diverge in regard to the safety and efficacy of antioxidant therapy, calling such data “conflicting and confusing.” In fact, the great preponderance of data suggests a harmless or even a synergistic effect with most high-dose dietary antioxidants.
- Is inconsistent in its recommendations, since antioxidants are found naturally in common foods; yet Dr. D’Andrea does not extend her warning to include antioxidant-rich foods, especially fruit and vegetables.
- Ignores the wide-scale use by both medical and radiation oncologists of synthetic antioxidants given by prescription in order to control the adverse effects of chemotherapy and radiation.
- Resorts to “red herring” arguments, citing negative studies in the realm of cancer prevention, rather than quoting studies that focus on the specific issue of concurrent treatment.
A version of this monograph will also be published in a medical journal in Spring 2006. However, I have specifically adapted a pre-publication version of the monograph in order to make it accessible to readers who do not necessarily have a scientific background or any prior knowledge of the subject.
We are offering this publication in electronic format. After purchasing, you can then print it out for your doctor, family members or friends.
In my opinion, the attack on antioxidants is the thin end of the wedge of a much broader attack against the complementary (CAM) approach to cancer. In fact, it is no exaggeration to say that the entire existence of a more humane form of cancer treatment is now imperiled by the coordinated power of medical orthodoxy. By purchasing this report you will be supporting an important effort to set the record straight about the actual track record of both chemotherapy and complementary medicine and to defend a patient’s right to choose less harmful treatments.
I hope that all our readers will support this effort to preserve a simple and inexpensive mode of therapy from unfair attack. Your financial support at this juncture is absolutely necessary if we are to continue to build support for less toxic approaches to cancer treatment.
In addition, if you also want to purchase a printed copy of my earlier book, Antioxidants Against Cancer, which deals in depth with this entire topic, or any of my other books, please review our books section of this web site by clicking here.
Dietary Antioxidants and Radiation Therapy
Category antioxidants, Radiation
An issue that is raising quite a bit of controversy and, at times, polarization of opinions among patients, physicians, and other healthcare professionals is the use of antioxidants for the prevention of cancer, of further dissemination of tumors, and for the overall improvement of the general well-being of patients. As cancer is known to be associated with oxidative damage to intracellular structures, exogenous replacement with antioxidant agents is thought by some to achieve replenishment of the depleted endogenous stores and, thus, be of benefit for cancer patients.[6,7] Although some practitioners view this use in a favorable light, in many instances, antioxidants are being taken by cancer patients on their own, with or without the knowledge or consent of their physicians.
Although the general controversy[8,9] on the benefits and risks deriving from the use of antioxidants is far from being resolved (owing to very limited clinical evidence available to make informed decisions), a specific issue that may affect how radiation therapy is being given and received was discussed at the conference by Brian Lawenda,[10] of the Naval Medical Center, San Diego, California.
Although antioxidants are believed to protect from the damage inflicted by radiation therapy in normal tissues, little is known about how they can affect the sensitivity of cancer cells to treatment. What if exogenous antioxidants also protect the tumor? Should physicians, and in particular radiotherapists, advise against their use for patients undergoing radiation treatments? Or should they, instead, recommend them to prevent damage to normal tissues associated with treatment?
Radiation therapy efficacy is linked to its ability to induce DNA damage and cell death by free-radical injury. To assess the influence of 2 antioxidants, vitamin E and green tea extract (GTE), on radiation treatment, C3H mice were grafted with human Mca-4 breast cancer cells and given high doses of vitamin E (10-fold the daily dose) and 650 mcg/g of GTE for 120 days. Tumors of 1 mm on day 4 were allowed to grow up to 8 mm. The mice received increasing doses of radiation therapy up to 85 Gy and were observed for 3 months. The study was powered to 80% and able to resolve a difference of 15%.[10]
No significant difference was seen in the amount of radiation required for tumor control between mice receiving antioxidants in their diet and control animals. There was, however, a trend toward a slightly higher dose needed for tumor eradication in antioxidant-treated mice. On the other hand, there was a significant difference in the damages induced by radiation treatment in the 2 groups: Vitamin E and GTE-treated mice showed partial protection of normal tissues from radiation injury (59% of GTE-treated mice presented severe tissue damage vs 70% of controls).[10]
Entry of antioxidant compounds was shown to occur in tumor and normal tissues with preferential accumulation of vitamin E in the muscle beneath the tumor. Accumulation of vitamin E was associated with an increase in apoptosis and a decrease in tumor cell proliferation. Similar results were obtained with GTE. Both antioxidants inhibited growth of tumor cells in vitro as determined by an MTT proliferation assay. Endothelial cell proliferation was not significantly affected by either antioxidant. There was, however, a trend toward an increase in pericyte proliferation and toward a decrease in cell migration at lower concentrations of antioxidant.
Microarray analysis of expression patterns of angiogenesis-related genes confirmed the in vivo antiangiogenic effect attributed to GTE that may underlie its effect on inducing slower tumor cell growth. Conversely, GTE-treated host stromal cells present in homogenized tissues showed increased expression of the proangiogenic vascular endothelial growth factor. Both GTE and vitamin E showed an antiangiogenic effect in vitro (related to tumor cells) and a proangiogenic effect in vivo (related to host stromal cells) that may explain the protective effect seen in vivo in normal tissues.[10]
Thus, Lawenda concluded, vitamin E and GTE appear to exert a protective effect on normal tissues without inducing a significant decrease in radiation efficacy. However, as noted by a conference attendee, because very high doses of radiation were used in this study, it is unclear whether the use of a lower dose of radiation would have unmasked a more substantial interference of the antioxidants with radiation treatment. It also still remains to be determined whether there is a synergistic effect on either process by vitamin E and GTE that is often taken concomitantly by cancer patients.
At the final question — “what, then, should we say to our patients?” — Lawenda[10] answered that because the available experimental evidence is still far from conclusive, caution is advised, and antioxidants should not be
