J Palliat Care 2020 Jan 3;35(1):53-58. Epub 2019 Feb 3.
Mayo Clinic Comprehensive Cancer Center, Rochester, MN, USA.
Background: Chemotherapy-induced peripheral neuropathy (CIPN) affects 30% to 40% of patients with cancer with long-lasting disability. Scrambler therapy (ST) appeared to benefit patients in uncontrolled trials, so we performed a randomized sham-controlled Phase II trial of ST.
Methods: The primary end point was "average pain" after 28 days on the Numeric Rating Scale. Each received ten 30-minute sessions of ST on the dermatomes above the painful areas, or sham treatment on the back, typically at L3-5 where the nerve roots would enter the spinal cord. Outcomes included the Brief Pain Inventory (BPI)-CIPN and the EORTC CIPN-20 scale. Patients were evaluated before treatment (day 0), day 10, and days 28, 60, and 90.
Results: Data regarding pain as a primary outcome were collected for 33 of the 35 patients. There were no significant differences between the sham and the "real" ST group at day 10, 28, 60, or 90, for average pain, the BPI, or EORTC CIPN-20. Individual responses were noted during the ST treatment on the real arm, but most dissipated by day 30. There was improvement in the sensory subscale of the CIPN-20 at 2 months in the "real" group ( = .14). All "real" patients wanted to continue treatment if available.
Discussion: We observed no difference between sham and real ST CIPN treatment. Potential reasons include at least the following: ST does not work; the sham treatment had some effect; small sample size with heterogeneous patients; misplaced electrodes on an area of nonpainful but damaged nerves; or a combination of these factors.