Mucke M, et al. – Here, the authors discuss the applicability of matrix electrodes for the reduction of ongoing pain in cancer patients via low–frequency electrical stimulation (LFS). In this feasibility study, findings are consistent with the concept of synaptic long–term depression in cancer pain induced after conditioning LFS. Effects persist throughout the 3–day follow–up, despite the short, but well–tolerated, treatment duration of 2 × 5 min/day.