RTOG 0537 Phase 2/3 Study Comparing Acupuncture-Like Transcutaneous Electrical Nerve Stimulation (ALTENS) versus Pilocarpine (PC) in Treating Early Radiation-Induced Xerostomia (RIX): Phase 3 Preliminary Analysis
Presenting Author: Rayimond K.W Wong, MD
Presenting Author Affiliation: McMaster University, Department of Oncology, Hamilton, ON, Canada
One of the major late toxicities of head and neck radiation therapy is radiation-induced xerostomia, or dry mouth from decreased salivary gland function. Xerostomia can be an enormous burden on patient’s quality of life, with a significant impact on speaking, eating, dental health, as well as general discomfort from the symptoms. With modern radiation techniques, namely intensity modulated radiation therapy (IMRT), providers are better able to reduce radiation dose to the salivary glands in order to attempt to decrease the incidence and severity of xerostomia. Yet, despite these techniques, xerostomia is still a major problem leading to decreased patient quality of life. In addition, a variety of medication and interventions have been tested, showing only modest improvement at best that is typically not long-term. Therefore, interventions or techniques to prevent or treat clinically significant xerostermia are sorely needed.
One promising intervention is Acupuncture-Like Transcutaneous Electrical Nerve Stimulation (ALTENS), which provides high intensity electrical stimulation to acupuncture points. This technique is relatively easy to perform and can be completed in approximately one hour. As such, the authors performed a Phase 2/3 trial comparing ALTENS to pilocarpine (an FDA approved medication for xerostomia) for the treatment of radiation induced xerostomia.
This study found no difference in xerostomia (dry mouth) between the two groups 9 months after radiation; however, at 15 months from radiation, 83% of patients receiving ALTENS reported improvement in xerostomia compared to 63% who received pilocarpine. In addition, ALTENS was much better tolerated with significantly less Grade 3 or less adverse events (22.5% vs. 62.5 %, p<0.001). The burden of xerostomia was measured using the 15-item University of Michigan Xerostomia-Related Quality of Life Scale (XeQOLS).
Overall, this in an important and well-performed trial, with potentially significant clinical implications for treating radiation induced xerostomia. Although, the trial did not meet its primary endpoint and thus cannot state yet that ALTENS is superior to pilocarpine, the fact at 15 months after randomization there were more positive responders in the ALTENS arm is an encouraging sign. The efficacy of ALTENS will more definitively be elucidated as the data from this trial continues to mature over the course of the coming year. At this time, it appears to be a low-risk method of treating xerostomia, that offers relief to a significant portion of patients.