Acupuncture may be effective in easing pain for people with breast cancer, according to results from a large, multi-site trial.Credit: UIG via Getty

One of the largest-ever clinical trials into whether acupuncture can relieve pain in cancer patients has reignited a debate over the role of this contested technique in cancer care.

Oncologists who conducted a trial of real and sham acupuncture in 226 women at 11 different cancer centres across the United States say their results — presented on 7 December at the San Antonio Breast Cancer Symposium in Texas — conclude that the treatment significantly reduces pain in women receiving hormone therapy for breast cancer. They suggest it could help patients stick to life-saving cancer treatments, potentially improving survival rates. But sceptics say it is almost impossible to conduct completely rigorous double-blinded trials of acupuncture.

Interest in acupuncture has grown because of concerns over the use of opioid-based pain-relief drugs, which can have nasty side effects and are extremely addictive. Many cancer centres in the United States therefore offer complementary therapies for pain relief. Almost 90% of US National Cancer Institute-designated cancer centres suggest that patients try acupuncture, and just over 70% offer it as a treatment for side effects1. That horrifies sceptics such as Steven Novella, a neurologist at Yale University School of Medicine and founder of the blog Science-Based Medicine. Acupuncture has no scientific basis, he says; recommending it is “telling patients that magic works”.

But Dawn Hershman, an oncologist at Columbia University Medical Centre in New York City, decided to investigate whether acupuncture could help to reduce the pain caused by aromatase inhibitors, one of the most commonly used treatments for breast cancer. These drugs lower oestrogen levels and, when taken over five to ten years, they reduce the risk that the cancer will recur. But they cause side effects, especially arthritis-like pain, which can cause up to half of women to take the medication irregularly, or to stop taking it altogether.

Meaningful relief

After a small trial at Columbia showed positive results2, Hershman and her colleagues conducted a larger one. The 226 women were placed into one of three groups: one that received acupuncture; another that got a sham treatment in which needles were inserted at non-acupuncture points, less deeply into the skin; and a third that received no treatment. The researchers trained the acupuncturists to deliver consistent treatments3. The women were asked to record their pain levels.

After a six-week course of treatment, ‘worst pain’ in the true-acupuncture group was about one point lower on a scale from zero to ten than in either the sham or no-treatment groups. This is a statistically significant effect, and larger than is seen with alternatives such as duloxetine, an antidepressant used to help reduce pain in people with cancer4. Meanwhile, the percentage of participants whose pain improved by at least two points (which Hershman describes as a “clinically meaningful” change) almost doubled, from around 30% in both control groups to 58% in the true-acupuncture group. Unlike with duloxetine, the benefits persisted after the acupuncture course had finished. Hershman concludes that acupuncture is a “reasonable alternative” to prescription medications such as duloxetine or opiates, neither of which were part of this study.

Rollin Gallagher, director of pain-policy research at the University of Pennsylvania in Philadelphia, and editor-in-chief of the journal Pain Medicine, welcomes the trial. “These are careful methodologists,” he says. “There is moderate to good evidence in clinical trials for acupuncture now, and this is another contribution.”

Placebo effect?

But sceptics have criticized the research. Regardless of how rigorous the trial was in other respects, the acupuncturists knew whether they were delivering real or sham treatment, says Edzard Ernst, emeritus professor of complementary medicine at the University of Exeter, UK. This could have influenced how the recipients responded, he says. “I fear that this is yet another trial suggesting that acupuncture is a ‘theatrical placebo’.”

But Jun Mao, chief of integrative medicine at the Memorial Sloan Kettering Cancer Centre in New York City, says that acupuncture trials such as Hershman’s are better blinded than studies of approaches such as palliative care, cognitive behavioural therapy or exercise, in which participants inevitably know what treatment they are receiving. Sceptics “accept trial results from those fields readily, but they make a special case against acupuncture”, he says. “It’s not fair to use that single argument to shut down the whole field.”

Gallagher says that many studies suggest that acupuncture triggers neurophysiological changes that are relevant to pain, in conditions from carpal tunnel syndrome to fibromyalgia5. Integrating acupuncture into mainstream medical care, rather than outsourcing it to independent, and perhaps unregulated, acupuncturists, minimizes the risk of lending authority to unscientific practitioners, he says. “That’s why we need to bring it in.”

For Hershman, the sceptics’ concerns risk losing sight of what’s best for patients. “To say that something that is pharmacologic is better, when it causes horrible toxicities, is also problematic,” she says. With acupuncture, “we tried to do the most rigorous study we could. At the end of the day, if it keeps somebody on their medication or improves the quality of their life, then it’s worth it.”