30 april 2012: aan onderstaand bericht hebben we het abstract van genoemde studie toegevoegd. Als u hier klikt kunt u het volledige studierapport gratis inzien.

9 oktober 2011: bron: Medscape

Wanneer patienten met prostaatkanker worden bestraald en aanvullend een lage dosis beta caroteen krijgen dan blijkt dit absoluut veilig en geen effect te hebben op de effectiviteit van de bestraling. Nog beter: het blijkt dat uit de groep die beta caroteen kreeg er 3% meer mensen na tien jaar nog steeds recidiefvrij waren. Dit is geen statistisch significant verschil maar wel bewijst dit dat beta caroteen gerust gegeven kan worden als voedingssupplement naast radiotherapie. Hier een citaat uit een artikel van Medscape waar als u hier klikt het hele artikel kunt lezen.

Low-dose beta-carotene supplements do not increase the risk of metastases or cancer mortality in men undergoing radiation therapy for prostate cancer, research shows.

In the current study, Dr. Margalit and her colleagues looked at PHS participants having radiotherapy for prostate cancer who had been randomized to take 50 mg of beta-carotene on alternate days or placebo.

During a median of 10.5 years of follow-up after radiation therapy, there was no significant difference between the groups in the risk of the study's primary endpoints, death from prostate cancer or bone metastases, according to the research team.

The hazard ratio for lethal prostate cancer was 0.72 for the beta-carotene group versus the placebo group (P=0.24), and the difference remained non-significant after adjustment for age at radiation therapy, prostate specific antigen level, Gleason score, and clinical stage.

At 10 years, 92% of men in the beta-carotene group and 89% in the placebo group remained free of prostate cancer recurrence.

Fewer than 5% of patients in the study smoked, so Dr. Margalit and her team were not able to look at whether beta-carotene might have a different effect in smokers.

Beta-carotene Antioxidant Use During Radiation Therapy and Prostate Cancer Outcome in the Physicians' Health Study

International Journal of Radiation Oncology*Biology*Physics

Volume 83, Issue 1, 1 May 2012, Pages 28–32

Beta-carotene Antioxidant Use During Radiation Therapy and Prostate Cancer Outcome in the Physicians' Health Study

Danielle N. Margalit, M.D., M.P.H.^∗^,^§^,^∗∗^,^,,
Julie L. Kasperzyk, Sc.D.^†^,^∗∗,
Neil E. Martin, M.D., M.P.H.^§,
Howard D. Sesso, Sc.D., M.P.H.^¶,
John Michael Gaziano, M.D., M.P.H.^‡^,^¶^,^‖,
Jing Ma, M.D., Ph.D.^†,
Meir J. Stampfer, M.D., Dr.P.H.^†^,^∗∗,
Lorelei A. Mucci, Sc.D., M.P.H.^†^,^∗∗

^∗ Harvard Radiation Oncology Program, Boston, Massachusetts
^† Channing Laboratory, Department of Medicine, Brigham & Women’s Hospital and Harvard Medical School, Boston, Massachusetts
^‡ Division of Aging, Brigham & Women’s Hospital and Harvard Medical School, Boston, Massachusetts
^¶ Division of Preventive Medicine, Brigham & Women’s Hospital and Harvard Medical School, Boston, Massachusetts
^§ Department of Radiation Oncology, Dana-Farber Cancer Institute, Brigham & Women’s Hospital and Harvard Medical School, Boston, Massachusetts
^‖ Veterans’ Affairs Boston Healthcare System, Boston, Massachusetts
^∗∗ Department of Epidemiology, Harvard School of Public Health, Boston, Massachusetts

Received 15 January 2011. Revised 30 April 2011. Accepted 10 May 2011. Available online 11 November 2011.

Purpose

The safety of antioxidant supplementation during radiation therapy (RT) for cancer is controversial. Antioxidants could potentially counteract the pro-oxidant effects of RT and compromise therapeutic efficacy. We performed a prospective study nested within the Physicians’ Health Study (PHS) randomized trial to determine if supplemental antioxidant use during RT for prostate cancer is associated with an increased risk of prostate cancer death or metastases.

Methods and Materials

PHS participants (383) received RT for prostate cancer while randomized to receive beta-carotene (50 mg on alternate days) or placebo. The primary endpoint was time from RT to lethal prostate cancer, defined as prostate cancer death or bone metastases. The Kaplan-Meier method was used to estimate survival probabilities and the log-rank test to compare groups. Cox proportional hazards regression was used to estimate the effect of beta-carotene compared with that of placebo during RT.

Results

With a median follow-up of 10.5 years, there was no significant difference between risk of lethal prostate cancer with the use of beta-carotene during RT compared with that of placebo (hazard ratio = 0.72; 95% confidence interval , 0.42–1.24; p = 0.24). After we adjusted for age at RT, prostate-specific antigen serum level, Gleason score, and clinical stage, the difference remained nonsignificant. The 10-year freedom from lethal prostate cancer was 92% (95% CI, 87–95%) in the beta-carotene group and 89% (95% CI, 84–93%) in the placebo group.

Conclusion

The use of supplemental antioxidant beta-carotene during RT was not associated with an increased risk of prostate cancer death or metastases. This study suggests a lack of harm from supplemental beta-carotene during RT for prostate cancer.

bestraling, radiotherapie, prostaatkanker, beta caroteen