Patients with colon cancer who used multivitamins during and after being treated with post-surgical chemotherapy did not reduce the risk of the cancer returning or their dying from it, according to researchers at Dana-Farber Cancer Institute.
In a study of patients with stage III colon cancer - characterized as cancer in the large bowel area with some cancer cells in a few nearby lymph nodes -- the researchers found that while multivitamin use had no beneficial effect on patients' outcomes, it also did not have a detrimental effect. The findings are reported online in the Journal of Clinical Oncology and later will be published in a print edition.
Kimmie Ng, MD, MPH, the paper's first author and a gastrointestinal oncologist at Dana-Farber, said that despite conflicting evidence on the efficacy of multivitamins to reduce cancer risk and death, studies suggest that approximately 30 percent of Americans take multivitamins to prevent and treat chronic diseases such as cancer. Among cancer survivors, between 26 and 77 percent report using multivitamins.
"With such a high proportion of cancer patients utilizing multivitamin supplements in the belief that it will help them fight their cancer, we felt it was important to really examine the data to see what impact multivitamins had on cancer recurrence and survival," said Ng.
The researchers used two questionnaires to track multivitamin use during and after chemotherapy. Of the 1,038 patients who completed the first survey, nearly half (518) responded they used multivitamins while receiving chemotherapy. Of the 810 cancer-free patients who completed the second survey six months after chemotherapy, more than half (416) reported multivitamin use.
Ng and her colleagues found no statistically significant differences in the rates of disease-free survival (the study's primary endpoint), recurrence-free survival, or overall survival between those who used multivitamins and those who didn't.