Objectives: Spinal cord stimulation (SCS) involves electrical stimulation of the dorsal spinal cord to disrupt the transmission of ascending pain signals. SCS has been used successfully to manage a variety of chronic pain conditions, but its efficacy in the treatment of pain syndromes in patients with cancer has not been established because most studies have involved a limited number of patients. The purpose of this study was to assess the efficacy of SCS in a large group of patients with cancer.
Materials and methods: A retrospective review was performed for all patients who had SCS trials and implants placed at Memorial Sloan Kettering Cancer Center between 2003 and 2021. Patients were divided into groups based on whether their pain could be directly attributed to cancer or its treatment (cancer dependent, n = 51) and those who had incidental pain unrelated to cancer (cancer independent, n = 22). The cancer-dependent group was further subdivided into those whose pain was directly related to primary tumor invasion or metastasis (cancer related, n = 26) and those whose pain was a result of cancer treatment such as chemotherapy or surgery (treatment related, n = 25). The primary outcomes were changes in pain scores and daily oral morphine equivalents (OMEs) before intervention to one year after implant. Secondary measures included the SCS trial success rate, change in pain scores immediately after the SCS trial, and change in pain scores immediately after the SCS implant.
Results: Most patients in the cancer-dependent pain group (59%) and the cancer-independent pain group (68%) had successful SCS trials and subsequently went on to have SCS implants placed. The patients with cancer-dependent pain as a whole had median reduction of 1.5 points (or 23%) on a 10-point pain score immediately after implant (p = 0.001), with the effect diminishing to a median reduction of 1 point (or 15%) by one year after implant (p = 0.027). The cancer-dependent pain groups did not have a significant reduction in daily OMEs, following implantation (p = 0.30), but the cancer-independent group did have a significant reduction (p = 0.01).
Conclusions: SCS can be considered as a treatment modality for patients with cancer whose pain is not adequately controlled with medical therapy or by less invasive interventions.
Keywords: Cancer pain; neuromodulation; oncologic pain; spinal cord stimulation.
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