Herbs, acupuncture and other so-called complementary treatments for cancer may not be completely innocuous.

A new study has found that many cancer patients treat these nostrums not as a supplement to conventional treatment but as an alternative. This, the researchers say, can be dangerous.

The observational analysis, in JAMA Oncology, used data on 258 complementary medicine users and 1,032 people in a control group.

Complementary therapies included herbs, vitamins, traditional Chinese medicine, homeopathy, naturopathy, yoga, acupuncture and others.

People who used complementary treatments were more often women, younger, privately insured and of higher socioeconomic status. They did not delay the start of conventional treatment any longer than others, but they had higher rates of refusal of surgery, chemotherapy, radiation and hormone treatments. They also had lower five-year survival rates and more than double the risk of death. The complementary treatments did no harm when conventional treatment was carried out simultaneously.

— New York Times News Service