Investigating high-concentration 8% capsaicin patch in chronic cancer-treatment related peripheral neuropathic pain.

Abstract

208 Background: Cancer-treatment related peripheral neuropathic pain is a challenging clinical problem as current interventions have limited efficacy and significant toxicities. This study aims to examine the analgesic effect of high-concentration 8% capsaicin patch in this cohort of patients. Methods: A single arm study was conducted. Patients with long-term peripheral neuropathic pain received a single application of 8% transdermal capsaicin patch to the affected area (chest wall, hands or feet). Assessments at baseline, 4 weeks and 12 weeks post-treatment included: Brief Pain Inventory (BPI) short form (pain severity and interference with function); Hospital Anxiety and Depression Scale (HADS). The primary efficacy measure was a clinically significant improvement in pain (≥ 30% reduction in total BPI score (responders) from baseline to 4 weeks and 12 weeks). Secondary efficacy measures assessed worst pain, function and associated changes in mood. Results: 19 patients, median age 61.5 all had peripheral neuropathic pain for a median of 2 years (IQR 1-3) following treatment for various types of cancer: gynecological (n = 2), breast (n = 6), colorectal (n = 8), multiple myeloma (n = 2) or other (n = 1). At 4 weeks, 37% (7/19) patients showed a clinically significant improvement in pain (≥ 30%). Of the 7 responders, 5 had > 50% reduction in pain. 16% (3/19) suggested a partial improvement (mean 17%). Of the patients reassessed at 12 weeks, 50% (7/14) were responders with all patients exhibiting a reduction in: worst pain score, -1.3 (95% CI: -2.5, -0.06; p = 0.04), interference with function, -10.9 (95% CI: -21.5, -0.4; p = 0.04) and HADS depression score, -1.7 (95% CI: -3.4, 0.02; p = 0.05). Total HADS score correlated with total BPI at 4 weeks (r = 0.68) and 12 weeks (r = 0.70). HADS depression score also correlated with BPI at 12 weeks (r = 0.73). All correlations were significant (p < 0.01). Conclusions: In patients with chronic, resistant, cancer-treatment related peripheral neuropathic pain, high-concentration 8% capsaicin patch may provide some benefit in pain severity, function and mood with the effect continuing at 12 weeks post-treatment. This may warrant further long-term follow up in a larger cohort.