Cancer patients who take vitamin E are probably not hindering the desired effects of radiation, according to a laboratory study done by radiation oncologists at Rush-Presbyterian-St. Luke's Medical Center in Chicago.
Researchers at Rush were concerned that patients who take vitamin E may be inadvertently providing protection for the cancer cells that are the target of radiation therapy. Radiation damage is one form of oxidation, and vitamin E's antioxidant properties presumably extend to cancer cells.
To determine if this were true, Rush researchers, led by Dr. Ed Blazek, director of radiation biology in the Rush department of radiation oncology, grew cells originating from human breast and prostate tumors in nutrient solutions containing several concentrations of vitamin E. The cells were then irradiated with the same daily doses used for patients.
The Rush team found that the tested concentrations of vitamin E did not interfere with the desired killing of cancer cells by radiation. An important limitation of this study, however, is that the level of vitamin E taken up by the cancer cells in laboratory culture has not yet been measured, and might be smaller than the level taken up by cells of a tumor in the patient's body. If so, it is still possible that vitamin E might worsen treatment outcomes.
Although no undesirable protection of cancer cells was found, the researchers issued a caution to those taking vitamin E and other alternative therapies. "Any drug that is taken during cancer radiotherapy or chemotherapy should be tested to prove that it does not protect the tumor cells, defeating the intended effect of the treatment," Blazek said.
Natural extensions of this work would include the addition of the drug pentoxifylline to vitamin E, since this combination has been reported to partially reverse radiation damage to normal tissue, the testing of vitamin C for radioprotection, and the testing of both vitamins E and C for protection from representative cancer chemotherapy drugs.
This research, performed by Drs. Alex Perez and Katherine Baker together with Dr. Blazek, was presented at the annual meeting of the Radiological Society of North America in Chicago.
Rush-Presbyterian-St. Luke's Medical Center includes the 809-bed Presbyterian-St. Luke's Hospital; 154-bed Johnston R. Bowman Health Center for the Elderly; Rush University (Rush Medical College, College of Nursing, College of Health Sciences and Graduate College); and seven Rush Institutes providing diagnosis, treatment and research into leading health problems. The medical center is the tertiary hub of the Rush System for Health, a comprehensive healthcare system capable of serving about two million people through its outpatient facilities and five member hospitals.