NEW STUDY CLARIFIES ROLE OF ANTIOXIDANTS DURING RADIATION TREATMENT

[Guest guest]

Hardly a surprise, but certainly news . . .

 

Ralph W. Moss, Ph.D. Weekly CancerDecisions.com

Newsletter #326 02/03/08

 

NEW STUDY CLARIFIES ROLE OF ANTIOXIDANTS DURING RADIATION TREATMENT

 

An important paper on the interaction of antioxidants and radiation

therapy was recently published in the International Journal of Cancer.

Interestingly, despite the significance of its findings, this study has

received virtually zero attention from the scientific community or the

media.

As background, in April 2005, Isabelle Bairati, MD, PhD, and her

colleagues at the Hôtel-Dieu de Québec Research Centre and the

 Université Laval completed a ten-year study on the interaction of

antioxidants and radiation therapy. This was hailed as the first

placebo-controlled, double-blind, randomized trial assessing the effect

of supplementation with antioxidant vitamins during radiation therapy.

The study concluded that supplements of synthetic beta-carotene (30 mg

per day) or alpha tocopherol (400 IU per day) had a harmful effect on

cancer patients. In particular, the authors claimed that the cancer

recurrence rate was 40 percent higher among patients who had been

randomly assigned to the supplementation arm of the trial. They

therefore called on patients and physicians to exert caution in using

antioxidants until new evidence could be provided by future trials.

 

Kedar Prasad, PhD, and other proponents of the concurrent use of

antioxidants during cancer treatment criticized the Bairati paper. They

were disappointed that Bairati and colleagues had used ordinary alpha

tocopherol as their choice of vitamin E when Prasad's previous work had

shown that it was not just alpha tocopherol but alpha tocopherol

succinate that had the anticancer efficacy. They also felt that natural

forms of the vitamin were more effective than synthetic, drug store-type

vitamins. But, by and large, the medical world accepted the Bairati

trial as definitive proof that antioxidants interfered with radiation

therapy. Word spread like wildfire in oncology circles, confirming a

long-held belief that antioxidants interfered with standard cancer

treatments such as radiation and chemotherapy. The take away message, as

stated in a Université Laval press release, was that " Supplements May

Speed Up Development of Cancer. " Advocates of co mplementary and

alternative medicine (CAM) were confounded by this large and impressive

study.

 

But now the other shoe has dropped.

In December 2007, Dr. Bairati and her Québec colleagues published a

major modification of their previous conclusions. Further analysis

revealed, they said, that the danger of synthetic antioxidants was

limited to one particular sub-population: cigarette smokers -

specifically, those who continued to smoke during radiation treatment.

The authors analyzed the outcome in 540 patients who had been given

radiation for head and neck cancers.

During the follow-up period, 119 patients had a recurrence of their

disease and 179 died. Smokers were the group with the worst prognosis.

However, astonishingly, smoking in the period leading up to or following

radiation therapy did not modify the effects of the two supplements. It

was only smoking during the course of radiation therapy that led to a

statistically significant increase in the risk of a recurrence. It was a

large enough increase to skew the statistics for the group as a whole,

leading to the erroneous co nclusion that antioxidants interfered with

radiotherapy in the general patient population.

 

Statistically, increased risk is generally expressed as a " hazard ratio "

(abbreviated HR). In this study, current smokers had an HR of 2.41 for

recurrence, in other words more than double the chance of a recurrence

compared to the rest of the patient population. The HR for death from

any cause was a similar 2.26. But the hazard ratio for dying of their

initial head and neck cancer was a whopping 3.38 in patients who got

radiation, smoked and also received a single synthetic antioxidant.

 

" These results could best be explained by the hypothesis that the

combined exposures reduced the efficacy of radiation therapy, " Bairati

and her colleagues now say. " Particular attention should be devoted to

prevent patients from both smoking and taking antioxidant supplements

during radiation therapy " (Meyer 2007).

 

According to the National Cancer Institute, 85 percent of head and neck

cancers are linked to tobacco use. (Alcohol use further exacerbates this

trend.) This has been widely known for years, and so it is shocking that

there are still people so hopelessly addicted to tobacco that they not

only continue to smoke after they've been diagnosed with head and neck

cancer but continue to smoke right through their radiation therapy. It

was in this subset of particularly unhealthy individuals that

antioxidants were associated with an increased risk of disease

progression. As Bairati and colleagues suggest, such individuals should

definitely not compound their problems by then taking a synthetic

antioxidant.

 

But the more important lesson for patients and practitioners is that

antioxidants do NOT generally interfere with the effects of radiation

therapy, as was previously suggested. They do NOT increase the risk of a

recurrence, of death from head and neck cancer, or of overall mortality

in the average patient. In this updated study, the harmful effect of

synthetic antioxidants was entirely limited to those relatively few

tobacco-addicted patients who continued to smoke during their radiation

therapy.

 

Thus, the major premise underpinning oncologists' condemnation of

antioxidants during radiation therapy has crumbled, although few seem to

have noticed so far.

ANTIOXIDANTS AND CANCER TREATMENT - A CHOICE OF REPORTS

 

In late 2005 the peer-reviewed journal CA (the American Cancer Society's

journal for clinicians working in the field of cancer) published a paper

strongly recommending against the use of antioxidants during cancer

treatment. In response to this paper we published a detailed report

titled Should Patients Undergoing Chemotherapy and Radiotherapy Be

Prescribed Antioxidants? This report analyzes the specific arguments

raised by D'Andrea and others against the use of antioxidants during

cancer therapy and finds that there is scant evidence to support the

widespread practice of forbidding antioxidants during cancer treatment.

 

Because this is a topic of such immediate importance to cancer patients,

we are now offering this report packaged with our newly published Do

Antioxidants Interfere With Radiation Treatment for Cancer? The combined

report, totaling 83 pages, gives an extensive overview of the entire

subject, including a detailed, point-by-point rebuttal of the specific

arguments put forward against the use of antioxidants during cancer

therapy.

 

" Do Antioxidants Interfere With Radiation Treatment for Cancer? "

received enthusiastic reviews from several prominent clinicians and

researchers:

 

" 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 ©

" A comprehensive rebuttal that is also an excellent review of this

complex topic. "

-Leanna Standish, ND, PhD, Bastyr University, Seattle

 

You can purchase the combined report - " Do Antioxidants Interfere With

Radiation Treatment for Cancer? " plus " Should Patients Undergoing

Radiation and Chemotherapy Take Antioxidants? " by going to:

https://webssl.cancerdecisions.com/list/optin.php?form_id=29

 

To purchase the single report " Do Antioxidants Interfere With Radiation

Treatment for Cancer? " please go to:

https://webssl.cancerdecisions.com/list/optin.php?form_id=28

 

MOSS REPORTS

We have Moss Reports on more than 200 different cancer diagnoses. You

can see the full list of reports, view a table of contents and read a

sample excerpt from one of the reports at our Web site,

www.cancerdecisions.com.

 

PHONE CONSULTATIONS - FINDING DIRECTION AND REGAINING A SENSE OF CONTROL

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We look forward to helping you.

--Ralph W. Moss, Ph.D.

 

References:

Bairati I, Meyer F, Jobin E, et al. Antioxidant vitamins supplementation

and mortality: a randomized trial in head and neck cancer patients. Int

J Cancer. 2006;119:2221-4.

Bairati I, Meyer F, Gélinas M, et al. Randomized trial of antioxidant

vitamins to prevent acute adverse effects of radiation therapy in head

and neck cancer patients. J Clin Oncol. 2005;23:5805-5813.

Bairati I, Meyer F, Gélinas M, et al. A randomized trial of

antioxidant vitamins to prevent second primary cancers in head and neck

cancer patients. J Natl Cancer Inst. 2005;97:481-488.

Meyer F, Bairati I, Fortin A, et al. Interaction between antioxidant

vitamin supplementation and cigarette smoking during radiation therapy

in relation to long-term effects on recurrence and mortality: A

randomized trial among head and neck cancer patients. Int J Cancer. 2007

Dec 4;122(7):1679-168.

 

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