Women with breast cancer who take megadoses of vitamins and minerals during their treatment are not doing themselves any good, according to Canadian researchers.

Alternative therapies such as megadose vitamins and minerals are commonly used by breast cancer patients, but their effect on recurrence and survival have rarely been evaluated.

Researchers looked at the survival and recurrence outcomes for 90 women with non-metastatic breast cancer diagnosed between 1989 and 1998, and who had been prescribed megadoses of beta-carotene, vitamin C, niacin, selenium, coenzyme Q10, and zinc in addition to standard therapies.

The 90 treated patients were prescribed combinations of three to six of the vitamins and minerals. A control group was matched to the vitamin/mineral patients for age at diagnosis, presence of axillary lymph node metastasis, tumor stage, grade, estrogen receptor status, year of diagnosis, and use of chemotherapy.

The average follow up of surviving patients was 68 months. Breast cancer-specific survival and disease-free survival times for the vitamin/mineral treated group were shorter than the survival times for the control group.

Overall survival rates were about the same for both groups, according to the report in the journal Breast Cancer Research and Treatment.

Other sources: Breast Cancer Research and Treatment