Prospective phase II study of the efficacy of transcutaneous electrical nerve stimulation in post-radiation patients

To evaluate the effectiveness of transcutaneous electrical nerve stimulation (TENS) delivered using an extra-oral device in patients with radiation-induced xerostomia.

Thirty oral cavity and oropharyngeal cancer patients post-adjuvant (n = 26) or definitive radiotherapy (n = 4) were enrolled in this study. The TENS electrode pads were placed externally on the skin overlying the parotid glands. Unstimulated whole saliva was collected for 5 min into graduated tubes using the low forced spitting method. The TENS unit was then activated and stimulated saliva was collected for an additional 5 min. The difference between unstimulated and stimulated saliva output was measured using the paired t-test. Linear regression was used to determine factors significantly influencing the improvement in salivary output.

Twenty-nine of 30 patients showed increased saliva flow during stimulation. A statistically significant improvement in saliva production (P < 0.05) during stimulation was noted. The mean unstimulated saliva flow was 0.056 ml/min and the mean stimulated saliva flow was 0.12 ml/min with a median increase of 0.06 ml/min. The interval to the application of TENS after radiotherapy significantly influenced the improvement in salivary flow.

Extra-oral application of TENS is effective in increasing the whole salivary flow in most of the post-radiated oral cavity/oropharyngeal cancer patients with xerostomia. TENS therapy may be useful as an effective supportive treatment modality in post-radiated oral cancer patients.