How Complementary Cancer Therapies Can Increase Risk of Early Death

People diagnosed with cancer have a multitude of treatment options, many of which are standard therapies that have been well-studied to improve their chances of surviving their disease or avoiding recurrence.

But people are increasingly also folding in complementary medicine approaches — which include nutrients, herbal remedies and other so-called natural supplements — with their cancer treatment regimes. While these are not nearly as well-studied as conventional therapies like surgery, radiation and chemotherapy, many people rely on them because they believe they can improve their chances of surviving their cancer or keeping recurrences at bay.

In a new study published in JAMA Oncology, researchers say that may not be the case. Dr. Skyler Johnson, chief resident in therapeutic radiology at Yale School of Medicine, and his colleagues analyzed data from nearly 1,300 people in the National Cancer Database with four common cancers: breast, prostate, lung or colorectal. 1,032 of those people used only conventional medicine, and 258 used at least one conventional treatment and one or more complementary medicine strategies (which were recorded as “other unproven cancer treatments administered by nonmedical personnel”). These included IV, oral and topical therapies made up of vitamins, minerals or herbal supplements, says Johnson.

Johnson found that people who added a complementary medicine approach had twice the risk of dying during the nine-year study compared to people who only chose conventional treatment. The people who opted to add complementary medicine were also more likely to refuse surgery, chemotherapy, radiation and hormone therapy compared to people who did not. Johnson says it was this avoidance of recommended treatment that was largely responsible for the higher early death rate; among people who did all of their conventional treatments and complementary medicine therapies, there was no difference in survival.

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“There is data showing that the majority of patients using complementary medicine therapies for cancer treatment are doing so because they believe they are going to improve their survival rates and cure rates,” says Johnson. “But they should know that there is no data suggesting that if you use these therapies you can improve your survival or cure rates.”

He says that when patients bring up complementary therapies, some doctors believe they “couldn’t hurt,” since they might make people feel more comfortable about their treatment. But “based on these data, there are clearly some issues with that approach,” he says.

He says there is some evidence from other studies that while many complementary approaches are “natural” and therefore believed to be safe, they can contain biologically active ingredients that can interact with chemotherapy and other cancer treatments, making them either less effective or even more toxic and detrimental to people’s health.

“We hope this information gives providers and patients pause to at least consider the chance that these complementary therapies might actually result in a detrimental effect,” he says.