And while the study, which involved nearly 700 women and was published in JAMA Oncology, didn’t look at the reasons behind their decisions, the study team called for improved training to help doctors better discuss the issue with their patients.
After surgery, women with breast cancer that hasn’t spread are often offered chemotherapy, since studies show it lowers the chances of the disease coming back. But some women decide against this.
To investigate what affects this decision, a team led by Professor Heather Greenlee from New York’s Columbia University Medical School invited 685 women with early-stage breast cancer to answer questions about their lifestyle, including whether they were taking a variety of complementary or alternative therapies, such as vitamin, mineral and dietary supplements, herbal/botanical products, and mind-body therapies such as yoga, massage, and meditation.
After a year, their medical records were examined to see whether they’d been offered chemotherapy, and whether they’d started treatment.
At the start of the study, 598 women (87 per cent) said they were using at least one form of complementary or alternative therapy, with 30 using five or more different treatments.
302 women were strongly recommended chemotherapy, of whom 34 decided against it. A further 379 were offered ‘discretionary’ chemotherapy, which 244 decided against.
A year later, among women for whom chemotherapy was strongly recommended, the more forms of complementary or alternative treatments a woman was using, the greater the likelihood that she hadn’t started chemo.
And women taking vitamin, mineral or other dietary supplements were also more likely not to have started chemotherapy.
However, there was no link between doing yoga, meditation or ‘practitioner-based’ therapies such as reiki, acupuncture or massage, and a decision not to have chemo.
Nor did taking any form of complementary or alternative therapy appear to influence women offered chemotherapy on a discretionary basis.
“In the group with a clear clinical indication for chemotherapy, users of [complementary or alternative therapies] were significantly over-represented among the relatively small group that did not receive this indicated treatment,” Greenlee’s team wrote.
But there were many possible explanations for the link, the team wrote, calling for more research to understand women’s decision-making processes.
Cancer Research UK’s Dr Emma Smith said there was evidence that complementary therapies can improve quality of life, and that it was every woman’s right to choose whether or not to have chemotherapy as part of their breast cancer treatment.
“But in making their decision they should not think of these therapies as a substitute for conventional cancer medicines, which have been researched in well-designed clinical trials, and are proven to be effective”.
She added that there was no evidence that complementary therapies can improve survival, and others can even be harmful, or interfere with effective treatments
“Women considering using complementary therapies should speak to their doctor first to make sure it’s safe.”
Dr Robert Zachariae, from Aarhus University Hospital in Denmark, said that studies showed many women who use complementary therapies fail to discuss this with their doctor, despite evidence it leads to better patient-doctor relationships, and higher patient satisfaction.
This, he said, highlights the urgent need to train oncologists to improve their ability to discuss such matters with their patients.
“This can best be done… by respectfully exploring patients’ preferences and beliefs, and by providing the best evidence-based information about treatment options in a non-judgmental fashion,” he wrote in a linked comment piece.
- Read more about complementary and altaernative therapies
Greenlee, H., Neugut, A., Falci, L., Hillyer, G., Buono, D., Mandelblatt, J., Roh, J., Ergas, I., Kwan, M., Lee, M., Tsai, W., Shi, Z., Lamerato, L., Kushi, L., & Hershman, D. (2016). Association Between Complementary and Alternative Medicine Use and Breast Cancer Chemotherapy Initiation JAMA Oncology DOI: 10.1001/jamaoncol.2016.0685