Acupuncture for xerostomia – a new trial with some most revealing findings

Radiation-induced xerostomia (RIX) is a common, often debilitating, adverse effect of radiation therapy among patients with head and neck cancer. Quality of life can be severely affected, and current treatments have limited benefit. Acupuncture is often recommended, but does it work? This study was aimed at finding out whether acupuncture can prevent RIX in patients with head and neck cancer undergoing radiation therapy.

The 2-center, phase 3, randomized clinical trial compared a standard care control (SCC) with true acupuncture (TA) and sham acupuncture (SA) among patients with oropharyngeal or nasopharyngeal carcinoma who were undergoing radiation therapy in comprehensive cancer centres in the United States and China. Patients were enrolled between December 16, 2011, and July 7, 2015. Final follow-up was August 15, 2016. Analyses were conducted February 1 through 28, 2019. Either TA or SA using a validated acupuncture placebo device were performed 3 times per week during a 6- to 7-week course of radiation therapy. The primary end point was RIX, as determined by the Xerostomia Questionnaire in which a higher score indicates worse RIX, for combined institutions 1 year after radiation therapy ended. Secondary outcomes included incidence of clinically significant xerostomia (score >30), salivary flow, quality of life, salivary constituents, and role of baseline expectancy related to acupuncture on outcomes.

Of 399 patients randomized, 339 were included in the final analysis, including 112 patients in the TA group, 115 patients in the SA group, and 112 patients in the SCC group. For the primary aim, the adjusted least square mean (SD) xerostomia score in the TA group (26.6 [17.7]) was significantly lower than in the SCC group (34.8 [18.7]) (P = .001; effect size = -0.44) and marginally lower but not statistically significant different from the SA group (31.3 [18.6]) (P = .06; effect size = -0.26). Incidence of clinically significant xerostomia 1 year after radiation therapy ended followed a similar pattern, with 38 patients in the TA group (34.6%), 54 patients in the SA group (47.8%), and 60 patients in the SCC group (55.1%) experiencing clinically significant xerostomia (P = .009). Post hoc comparisons revealed a significant difference between the TA and SCC groups at both institutions, but TA was significantly different from SA only at Fudan University Cancer Center, Shanghai, China (estimated difference [SE]: TA vs SCC, -9.9 [2.5]; P < .001; SA vs SCC, -1.7 [2.5]; P = .50; TA vs SA, -8.2 [2.5]; P = .001), and SA was significantly different from SCC only at the University of Texas MD Anderson Cancer Center, Houston, Texas (estimated difference [SE]: TA vs SCC, -8.1 [3.4]; P = .016; SA vs SCC, -10.5 [3.3]; P = .002; TA vs SA, 2.4 [3.2]; P = .45).

The authors concluded that this randomized clinical trial found that TA resulted in significantly fewer and less severe RIX symptoms 1 year after treatment vs SCC. However, further studies are needed to confirm clinical relevance and generalizability of this finding and to evaluate inconsistencies in response to sham acupuncture between patients in the United States and China.

In essence this two-centre study shows that:

• real acupuncture is better than usual care, but the effect size is small and of doubtful clinical relevance;
• real acupuncture is not significantly better than sham acupuncture;
• the findings differ remarkably between the US and the Chinese centre.

I find the last point the most interesting one. We know from previous research that acupuncture studies from China are notoriously unreliable; they never report a negative result and there is evidence that data fabrication is rife in China. The new findings seems to throw more light on this notion. In the US centre, real and sham acupuncture generated practically identical results. By contrast, in the Chinese centre, real acupuncture generated significantly better results than sham. The authors offer several hypotheses to explain this remarkable phenomenon. Yet, in my view, the most likely one is that Chinese researchers are determined to show that acupuncture is effective. Thus all sorts of unconscious or even conscious biases might get introduced into such studies.

In essence, trial therefore confirms that acupuncture is little more than a theatrical placebo, particularly if we consider the US data which, in my opinion, are more trustworthy.

Lorenzo Cohen, Professor of Palliative, Rehabilitation, and Integrative Medicine and director of the Integrative Medicine Program as well as senior author of the paper unsurprisingly disagrees. He was quoted saying: “The evidence is to a point where patients should incorporate acupuncture alongside radiation treatment as a way to prevent the severity of dry mouth symptoms. I think with this study we can add acupuncture to the list for the prevention and treatment of xerostomia, and the guidelines for the use of acupuncture in the oncology setting should be revised to include this important chronic condition.”

Who do you think is closer to the truth?