Concordance of patient- and clinician-reported outcomes of acute radiation dermatitis in breast cancer

Background and purpose: The study evaluated the concordance between patient-reported outcomes (PRO) and clinician-reported outcomes (CRO) of acute radiation dermatitis (RD) symptoms following adjuvant radiotherapy for early-stage and locally advanced breast cancer.

Material and methods: This is a secondary analysis of a multi-center randomized phase 3 trial (376 patients). Ordinal logistic regression analysis was used to compare the Skin Symptom Assessment (SSA) independently reported by both patients and clinicians. Concordance between patient- and clinician-reported SSAs for RD symptoms was measured by percent concordance, concordance index (C-statistic), and Cohen's Kappa. Analyses were performed across all patients in the original modified intention-to-treat analysis and those with only grade 2-3 (CTCAE) RD.

Results: PROs were significantly more severe than CROs across all RD symptoms (Odds Ratio [OR] > 1; p < 0.0001). Pigmentation (OR 5.4), blistering/peeling (OR 4.0), and pain/soreness (OR 3.9) were the most differentially reported symptoms. Poor-to-low concordance was noted between patient- and clinician-reported SSAs for all RD symptoms for the entire cohort (percent concordance < 50%, C-statistic 0.52-0.63, Cohen's Kappa 13.9-23.4%) and those with grade 2-3 RD (percent concordance < 50%, C-statistic 0.56-0.66, Cohen's Kappa 2.0-24.5%). Similarly, poor-to-low concordance was noted in both Mepitel film and standard-of-care arms.

Conclusion: PROs and CROs have poor concordance in breast RD, and patients report worse outcomes than clinicians, regardless of RD severity or prophylaxis. PROs must be further integrated into routine clinical practice and clinical trial design to reduce the risk of underreporting symptoms.