Calmare therapy (CT) may be an effective option for treating cancer-related neuropathic pain (CNP), according to a pilot study published in issue of the European Journal of Oncology Nursing.1
Also known as scrambler therapy, the novel, noninvasive approach consists of applying surface electrodes around the surface of painful areas to ‘scramble’ afferent pain signals and replace them with synthetic ‘non-pain’ information.
The open-label study included 20 patients with the 3 most common causes of CNP: chemotherapy-induced peripheral neuropathy (CIPN; n=6), metastatic bone pain (n=7), and post-surgical neuropathic pain (n=7).
CT was applied for 40 minutes each day for 10 consecutive days; up to 2 days could be skipped at weekends. The primary endpoint was pain score, as evaluated on an 11-point numerical rating scale (NRS). Other measures included the Brief Pain Inventory (BPI) and opioid consumption.
Results at 1 month showed that CT yielded a 50% decrease in mean pain scores from baseline (3.7 vs 7.4, P < .001); 15 patients (75%) experienced a 30% or greater decrease in pain (30% – 50%, 45%; >50%, 30%). Pain relief was significant across pain subtypes, including CIPN (3.1 vs 6.1, P =.027), metastatic bone pain (3.1 vs 7.4, P = .018), and post-surgical neuropathic pain (5.2 vs 8.5, P = .028).
The approach was also associated with significant improvements in all 7 domains of the Brief Pain Inventory (BPI, P <.001 to P = .016)), and decreased use of opioid rescue therapy (P = .050). Half the patients treated expressed slight to moderate satisfaction with CT, while the other half remained neutral.
“The most important thing to note is that, without adding medications or increasing doses of existing prescriptions, this treatment provided patients with clinically significant relief, as 75% of patients experienced a 30% or greater improvement in pain,” Bob Twillman, PhD, executive director of the American Academy of Pain Management, told Clinical Pain Advisor.
Further Research Needed
The pilot study is primarily limited by its small sample size and open-label nature. Although larger studies can be conducted, the open-label aspect is not likely to be amenable to manipulation, Dr Twillman said.
“It would be really nice to have a double-blind, placebo-controlled, randomized clinical trial, but the nature of [CT] doesn’t really lend itself to even a single-blind trial. Thus, we will need to see a series of replications using a similar design. At some point, it might be possible to examine whether using Calmare therapy could enable patients to taper doses of opioids and other medications previously used to treat their pain,” Dr Twillman said.