Multivitamins during and after chemotherapy has no effect on improving the risk of colon cancer or keep a patient from dying, report .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.
Dr. Kimmie Ng, the paper's first author and a gastrointestinal oncologist at Dana-Farber, said that there has been conflicting evidence on the efficacy of multivitamins to reduce cancer risk and death.
"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.
The researchers failed to find any 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.
They also found that an array of factors, including socio-economic status, household income, multivitamin and individual vitamin dosage, and consistency of multivitamin use had no effect on their findings.
However, they did find a small beneficial association between age and weight and the use of multivitamins while receiving chemotherapy.
Those 60 and younger experienced some survival benefit, as did obese patients.
There were no benefits for either subgroup when the multivitamins were taken after chemotherapy was completed.
"This study adds to a growing body of research that questions the purported benefit of multivitamin use, and it underscores the need to investigate the use of individual vitamins, such as vitamin D, which may, in fact, provide real benefit," said Dr. Charles Fuchs,
He noted that the average multivitamin typically contains only a small to modest amount of vitamin D.
The findings are published in the Journal of Clinical Oncology and later will be published in a print edition.