Measuring the severity of topical 5-fluorouracil toxicity.

Abstract

Topical 5% 5-fluorouracil (5-FU) is known to cause toxicity, such as erythema, pain, and crusting/erosions. We sought to develop a scale to measure this toxicity and test the scale for reliability. A scale was developed involving four parameters: erythema severity, percentage of face involved in erythema, crusting/erosions severity, and percentage of face involved in crusting/erosions. Thirteen raters graded 99 sets of photographs from the Veterans Affairs Keratinocyte Carcinoma Chemoprevention (VAKCC) Trial using these parameters. Intraclass correlation overall for 13 raters was 0.82 (95% CI 0.77-0.86). There was no statistically significant trend in reliability by level of training in dermatology. This scale is a reliable method of evaluating the severity of toxicity from topical 5-fluorouracil and can be used by dermatologists and nondermatologists alike.