Natural not always good for you, warn cancer doctors

Cancer patients who seek the perceived natural benefits of alternative therapies may be at risk of serious adverse effects, according to two new studies.

Professor Stephen Clarke told the Clinical Oncological Society of Australia’s Annual Scientific Meeting on 19 November that an alarming number of cancer patients experiment with complementary and alternative medicines, risking dangerous interactions with conventional medicines.

Professor Clarke, a medical oncologist and clinical pharmacologist from Sydney’s Concord Hospital, said mixing prescribed anticancer therapies with complementary and alternative medicines could reduce the effectiveness of conventional medicines and produce a harmful toxic cocktail.

"Many cancer patients are understandably interested in the perceived benefits of complementary and alternative medicines, however patients need to be aware that mixing these therapies with conventional medicines can cause serious harm," he said.

"From what we know, many patients are reluctant to discuss their interest in complementary and alternative medicines with their doctors, whom they believe will be dismissive, leading to a dangerous breakdown in doctor-patient communication.

"Cancer clinicians need to take their patients’ interest in alternative therapies seriously, while patients need to understand that mixing conventional and unconventional therapies can reduce the efficacy of prescription medicines and increase overall drug toxicity."

Geeta Sandhu, a cancer pharmacist and safe medicines specialist from Brisbane’s Princess Alexandra Hospital, said more than half of the hospital’s day therapy cancer patients surveyed over a month used complementary and alternative therapies, "almost of all of which could interact adversely with their prescribed anticancer therapy."

"When we explained the risks and benefits, most patients appreciated the advice and made an informed choice to stop taking complementary and alternative therapies," she said. "Our study mirrors trends in the literature elsewhere and emphasises the importance of open communication between patient and doctor and the need for more research."

More research into the combined effects of conventional and unconventional therapies was critical, Professor Clarke said.

(Source: Clinical Oncological Society of Australia: Clinical Oncological Society of Australia Annual Scientific Meeting, Gold Coast: November 2009)