Multivitamins Don't Reduce Colon Cancer Risk

Vitamins also failed to lower the risk of recurrence in survivors, study finds

Taking multivitamins does not reduce colorectal cancer patients' risk of dying or, among survivors, the likelihood that the cancer will return, a new study shows.

Between 26 percent and 77 percent of cancer survivors in the United States say they take multivitamins in the belief that it will help them fight their cancer, noted the researchers at the Dana-Farber Cancer Institute in Boston.

In this study, patients with stage III colon cancer (cancer in the bowel area with some cancer cells that have spread to a few nearby lymph nodes) were asked to complete questionnaires about their use of multivitamins during and after post-surgery chemotherapy.

Nearly half of the 1,038 patients who completed the first survey said they used multivitamins while receiving chemotherapy. More than half of the 810 cancer-free patients who completed the second survey six months after chemotherapy said they were taking them.

There were no significant differences in rates of disease-free survival, recurrence-free survival, or overall survival between patients who took multivitamins and those who did not, said the researchers.

The researchers did find a small benefit associated with multivitamin use, age and weight during chemotherapy. Patients 60 and younger and those who were obese experienced a small survival benefit during chemotherapy, although taking the vitamins after it ended did not boost survival in either group.

Researchers also found there was no downside to taking the multivitamins: although there was no overall survival benefits, there were no detrimental effects observed, either.

The findings were not affected by other factors such as socioeconomic status, household income, multivitamin and individual vitamin dosage, or consistency of multivitamin use.

The study appears online and in an upcoming print issue of the Journal of Clinical Oncology.

"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," study senior author Dr. Charles Fuchs, director of gastrointestinal oncology at Dana-Farber, said in a news release from the institute.

More information

The American Cancer Society has more about colorectal cancer.

-- Robert Preidt

SOURCE: Dana-Farber Cancer Institute, news release