Acupuncture is effective for the treatment of pain that is related tumors and to cancer surgery but not pain due to chemotherapy, radiation therapy (RT), or hormone therapy, according to the largest meta-analysis to date on the use of the Chinese modality in this setting.
Tumors, which may press on bones or organs, and surgical incisions, which disrupt tissue, generally cause "nociceptive" pain, which means it is visceral and somatic and thus is more amenable to acupuncture, say the authors, led by H.Y. Chiu, PhD, RN, from the Taipei Medical University in Taiwan.
The toxic effects resulting from chemotherapy and RT are largely associated with neuropathic pain, which is "complicated" and therefore more difficult to treat, the investigators summarize.
The nonsignificant treatment effects seen with hormone therapy–related pain may be due to the inclusion of only three such studies in the analysis, they note.
A total of 36 randomized controlled trials involving 2213 patients were included in the study, which was published online February 7 in the European Journal of Cancer Care.
The overall effect of acupuncture on cancer-related pain was –0.45 (95% confidence interval [CI], –0.63 to –0.26). However, study subanalysis indicated that acupuncture relieved malignancy-related and surgery-induced pain (effect size, –0.71 [95% CI, –0.94 to –0.48] and –0.40 [–0.69 to –0.10]) but not chemotherapy- or RT-induced and hormone therapy–induced pain.
However, two acupuncturists at major US cancer centers, both of whom are lead authors of clinical trials included in the meta-analysis, had doubts about the new results.
Wiedong Lu, MB, MPH, PhD, lead oncology acupuncturist at the Dana Farber Cancer Institute in Boston, Massachusetts, said that the lack of efficacy seen for pain related to RT, chemotherapy, and hormonal therapy may be the result of insufficient familiarity with the different types of pain among the various trialists.
"In my experience, acupuncture works reasonably well when treating chemo-related pain, such as chemotherapy-induced neuropathy," he told Medscape Medical News.
Dr Lu agreed with the study authors that chemotherapy- and RT-caused pain are more neuropathic in nature and more difficult to treat. But he also said the "treatment dosage needed might be different than other types of pain."
Ting Bao, MD, DABMA, MS, director of integrative breast oncology at Memorial Sloan Kettering Cancer Center in New York City, believes the results might be explained by factors other than actual effectiveness.
"It does not make too much sense to me that only tumor-related pain and surgery-induced pain were relieved by acupuncture," she told Medscape Medical News.
The lack of efficacy seen with the other three types of pain "may be the results of different study design rather than the distinct differences in response to acupuncture in different type of cancer/cancer-treatment related pain," she said.
Dr Bao said the results suggest that there is a lot of heterogeneity in the study designs, especially control group design.
Instituting uniform protocols for the study of acupuncture in oncology is one of the tasks of the Society for Integrative Oncology said Dr Wu. Meanwhile, Dr Wu and fellow acupuncturists at Dana-Farber's Zakim Center have also developed acupuncture practice protocols and guidelines in the past few years. In 2016, the field took a big step forward when the National Cancer Institute held a historical conference, "Acupuncture for Cancer Symptom Management." There is also now a new subspecialty in the field called "oncology acupuncture."
"The future is bright for the new subspecialty because we are seeing more scientific evidence supporting the use of acupuncture in cancer care," said Dr Wu, who noted that the treatment is inexpensive compared with drug therapy.
He noted, however, that factors such as insurance reimbursement and practice space in cancer centers may limit uptake.
More on the Study
In the meta-analysis, the mean age of patients was 56.7 years. Of the 36 randomized trials, 17 focused on pain related to malignancy, 11 on chemotherapy or RT, 5 on surgery, and 3 on hormone therapy.
Acupuncture therapies included manual needle acupuncture, electroacupuncture, wrist-ankle acupuncture, scalp acupuncture, auricular acupuncture, moxibustion, and transcutaneous electrical acupoint stimulation.
Only four trials explicitly mentioned that the acupuncture treatment was performed on the basis of Traditional Chinese Medicine (TCM) theory. Acupuncture is one of the cornerstones of TCM and involves the application of needles, heat, pressure, and other treatments at specific sites of the body, known as acupoints, to affect the physical functions of the body.
Twenty trials in the study used analgesics as a comparator, and 10 trials applied sham controls that included minimal or superficial needles at nonacupoints, retractable or blunt needles at nonacupoints, and blunt needles at acupoints.
Dr Bing says acupuncture will likely continue to grow in use at major cancer centers. "The future calls for more rigorous research to study the mechanism of action and provide further evidence of efficacy, as well as how more acupuncture service can be integrated into cancer care," she said.
The study was supported by grants from the Ministry of Science and Technology, Taiwan.
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Cite this: Acupuncture Reduces Two Types of Cancer Pain - Medscape - Mar 15, 2017.