Correlation of CTCAE and patient-reported breast radiation dermatitis symptom scores.

Background and purpose: Clinicians use the CTCAE scale to grade radiation dermatitis (RD) based on edema, erythema, and desquamation. The purpose of this study was to correlate the CTCAE scores with the severity of patient-reported symptoms using a skin symptom assessment (SSA) and the Radiation-Induced Skin Reaction Assessment Scale (RISRAS).

Materials and methods: This is a secondary analysis of a randomized controlled trial involving 376 patients receiving Mepitel Film or standard-of-care for RD prophylaxis. The highest symptom categories for SSA and patient-component RISRAS assessments were selected from all time points, and a summary analysis and Spearman correlation coefficient was calculated for patients with CTCAE Grades 0, 1, 2, 3, and Grade 2/3, respectively. Analyses were conducted across all patients, within each treatment arm, and between arms in patients with only Grade 2 or 3 toxicity.

Results: Weak correlations between CTCAE scores and all patient-reported skin symptoms were found across the entire cohort and each treatment arm (p < 0.05). Patients with Grade 2 (n = 72) and Grade 3 RD (n = 24) reported similar rates of patient-reported moderate-to-severe skin symptoms (11-72% vs 14-79%), with no significant difference in rates of individual moderate-to-severe symptom between these cohorts (p > 0.05). Between treatment arms, rates of patient-reported moderate-to-severe scores were similar for most symptoms.

Conclusion: CTCAE RD scores are weakly correlated with patient-reported skin symptoms and cannot distinguish between patients with severe patient-reported outcomes. Clinicians should consider the limitations of CTCAE grading and incorporate patient-reported outcomes within clinical practice.