Topical Diclofenac for Prevention of Capecitabine-Associated Hand-Foot Syndrome: A Double-Blind Randomized Controlled Trial.

Purpose: Hand-foot syndrome (HFS) is a dose-limiting side effect of capecitabine. Celecoxib prevents HFS by inhibiting cyclooxygenase-2 (COX-2) that is upregulated because of the underlying associated inflammation. However, systemic side effects of celecoxib have limited routine prescription. Topical diclofenac inhibits COX-2 locally with minimal risk of systemic adverse events. Therefore, we conducted this study to assess the efficacy of topical diclofenac in the prevention of capecitabine-induced HFS.
Methods: In this single-site phase III randomized double-blind trial, we enrolled patients with breast or GI cancer who were planned to receive capecitabine-based treatment. Participants were randomly assigned in a 1:1 ratio to receive topical diclofenac or placebo gel for 12 weeks or until the development of HFS, whichever occurred earlier. The primary end point was the incidence of grade 2 or 3 HFS (Common Terminology Criteria for Adverse Events version 5), which was compared between the two groups using simple logistic regression.
Results: In total, 264 patients were randomly assigned to receive topical diclofenac gel (n = 131) or placebo (n = 133). Grade 2 or 3 HFS was observed in 3.8% of participants in the diclofenac group compared with 15.0% in the placebo group (absolute difference, 11.2%; 95% CI, 4.3 to 18.1; P = .003). Grade 1-3 HFS was lower in the diclofenac group than in the placebo group (6.1% v 18.1%; absolute risk difference, 11.9%; 95% CI, 4.1 to 19.6). Capecitabine dose reductions because of HFS were less frequent in the diclofenac group (3.8%) than in the placebo group (13.5%; absolute risk difference, 9.7%; 95% CI, 3.0 to 16.4).
Conclusion: Topical diclofenac prevented HFS in patients receiving capecitabine. This trial supports the use of topical diclofenac to prevent capecitabine-associated HFS.