Î’-carotene is safe for patients receiving radiotherapy for prostate cancer

The study found that supplementing low doses of beta-carotene in prostate patients receiving radiation therapy did not increase the risk of cancer metastasis or death.

Lead author, Danielle N of the Dana Farber Cancer Institute in Boston. Dr. Margalit told Reuters Health: Based on a prospective analysis of 383 participating Physician Health Study (PHS) participants, the results were encouraging.

"However, the results of this experiment cannot be directly used to evaluate the safety of other antioxidant pairs," she added. At the annual meeting of the American Society for Radiotherapy and Oncology in Miami, Dr. Margalit published the results of the study.

Dr. Margalit said in an interview: “Starting to worry about the use of antioxidants during radiation may increase the chance of treatment failure, given that supplemental antioxidants will counteract the role of pro-oxidants in radiation therapy.”

The large-scale study shows that this may be the case of randomized patients taking placebo or vitamin E plus beta-carotene in head and neck cancer patients, and the incidence of recurrence in smoking patients taking antioxidants increases.

In the latest study, Dr. Margalit and her colleagues observed data from patients who participated in PHS. These patients were undergoing radiation therapy for prostate cancer. They were randomly divided into two groups, taking beta carotene and placebo, respectively. Dosed once a day.

According to the research team, after a 10.5 year follow-up observation of patients receiving radiation therapy, it was found that there was no significant difference between the two study groups in the primary study endpoint, prostate cancer deaths, and bone metastases. The risk ratio for fatal prostate cancer in the β-carotene group was 0.72 (P=0.24) compared to placebo and adjusted (radiotherapy patient age, prostate specific antigen level, prostate cancer Gleason score, clinical After staging, this difference is not significant.

In 10 years, 92% of patients taking beta-carotene and 89% of men taking placebo had no recurrence of prostate cancer.

Less than 5% of researchers smoked, so Dr. Margalit's group could not conclude that beta-carotene had a different effect on smokers.

Dr. Margalit said: “It is still very controversial whether taking antioxidants during radiation is harmful.” Patients receiving radiation therapy often supplement high doses of antioxidants. She continued: "We did find that some patients spent a lot of money on high-dose antioxidants. The study did not evaluate the safety of these products."

In Dana Farber, she said that based on this study, she and her colleagues advised patients to take standard multivitamins. It also persuades patients who are receiving radiation therapy not to worry about taking antioxidant-rich fruits and vegetables.

Once the second part of the experiment, a similar long-term follow-up, was completed, Dr. Margalit and her colleagues are planning to implement a similar PHS result analysis to determine whether vitamin C and vitamin E may affect the effectiveness of radiation therapy for prostate cancer patients. .