Using the skindex-16 and common terminology criteria for adverse events to assess rash symptoms: Results of a pooled-analysis (N0993)

Background Historically, skin toxicity has been assessed in prospective clinical trials using the clinician-reported National Cancer Institute Common Terminology Criteria for Adverse Events (CTCAE). The patient-reported Skindex-16 measures symptoms and perceptions of toxicity. This study was designed to compare information provided by these two measures. Methods Data were compiled from three placebo-controlled North Central Cancer Treatment Group studies (N06C4, N03CB, N05C4) having rash prevention as the primary objective. All used the Skindex-16 and CTCAE at baseline, weekly during treatment and during a minimum 2-week follow-up period. Statistical procedures, including Pearson correlations, were utilized to determine relationships between adverse event (AE) grades and Skindex-16 scores. Results Four hundred and twelve individual patients provided data (median age, 61; 134 male). Patients' Skindex-16 score results show a 0.9 overall mean (range 0-6 with 6 being worse symptoms), a 0.4 baseline mean (range, 0-4.3) and a 1.3 end-of-treatment mean (range, 0-5.9). Ninety-three, 142 and 177 patients experienced a grade 0, 1 and 2+ CTCAE skin toxicity, respectively. Baseline Skindex-16 scores had relatively low correlation with CTCAE grades. The correlation of rash grade with Skindex-16 scores ranged from r=0.49 with the function subscale to r=0.62 with the symptom subscale. The highest correlations of the maximum grade of any dermatological AE with the Skindex-16 were r=0.48 for the total score and r=0.55 for the symptom subscale. Conclusions The data reported support the decision to include both measures in a clinical trial to assess the patient experience, as each measure may specifically target varying symptoms and intensities.