Complementary “medicines” thought to help people with cancer, such as fish oil, ginger, green tea and licorice can negatively interact with medical treatments, causing harm, new research suggests.
A review of the most common “complementary medicines” inquired about at Melbourne’s Peter MacCallum Cancer Centre over two years found that they all had the potential to disturb chemotherapy, radiation therapy or surgery, putting patients at risk.
The top 10 products asked about by patients were fish oil, turmeric, coenzyme Q10, milk thistle, green tea, ginger, lactobacillus, licorice, astragalus and reishi mushroom. The study excluded vitamins and minerals because they are often safely prescribed to people with cancer.
Senior Pharmacist at the hospital’s Medicines Information Centre, Sally Brooks, said although some of these products might be harmless in low dietary doses, high doses of fish oil and ginger could cause bleeding in patients with a low platelet count. Others such as turmeric could increase or decrease the effects of chemotherapy drugs, compromising treatment.
“If it is increasing the effects of chemotherapy, it can actually cause toxicity to the patient and if it’s decreasing the effects of chemotherapy it may actually reduce the effectiveness of that patient’s treatment,” she said.
It was also possible that products with anti-oxidants in them could reduce the effects of radiotherapy and that products that increase oestrogen in the body might be harmful to women with hormone sensitive cancers such as breast and ovarian cancer.
“Milk thistle may possibly have oestrogenic effects,” she said.
Ms Brooks said while there was limited evidence from human trials demonstrating the effects of these products on patients with cancer, laboratory studies had flagged the potential for damage.
President of the Clinical Oncology Society of Australia Associate Professor Sandro Porceddu said patients could wrongly assume products labelled “complementary” will “complement” conventional cancer therapies and that anything natural must be safe.
“Until we know more, it’s best to err on the side of caution and for patients to discuss with their healthcare provider any complementary or alternative therapies they are using or considering using, in order to minimise risk,” he said.
There are estimates up to 70 per cent of cancer patients use complementary and alternative treatments for cancer. While some of these treatments, such as meditation, are known to be safe, others, such as apricot kernels, have killed people.
The research is being presented at the Clinical Oncology Society of Australia’s annual scientific meeting in Melbourne today (Wednesday).
Another pilot study being presented at the conference by head of psychiatry at Peter Mac, Jeremy Couper, found that patients with head and neck cancers benefited from mindfulness-based stress reduction techniques taught to them by a psychologist in seven one-on-one sessions.
Dr Couper said the trial involving 19 patients found nearly 90 per cent of them practiced the meditation techniques they were taught at least three times a week and that those who did it the most experienced a better quality of life and lower cancer-related stress, anger, fatigue, depression and anxiety.
He is now planning a randomised controlled trial in a larger group of patients to determine whether the meditation led to those improvements, rather than sessions with a psychologist sympathetic to their plight.
People with head and neck cancers suffer high rates of depression and anxiety, partly because the treatment can be distressing. Side effects often include difficulty breathing, speaking and chewing, painful swallowing and facial disfigurement.