77 LONG-TERM PATIENT REPORTED OUTCOMES IN A RANDOMIZED CONTROLLED TRIAL OF MEPITEL FILM VERSUS STANDARD OF CARE IN BREAST RADIATION THERAPY

Purpose: This study aims to evaluate the long-term skin-related patient-reported outcomes (PROs) of a randomized controlled trial (RCT) comparing Mepitel Film (MF) to standard of care (SOC) for the prevention of acute radiation dermatitis (ARD) in breast cancer patients undergoing radiation therapy (RT). Materials and Methods: Patients were contacted via telephone at 6-, 12-, and 24-months post-RT to complete the Skin Symptom Assessment (SSA) and Radiation-induced Skin Reaction Assessment Scale (RISRAS). SSA and RISRAS scores at follow-up visits were compared to baseline using generalized estimation equation with Poisson distribution and log link function. To account for multiple testing, the Bonferroni-adjusted p-value of <0.001 was considered statistically significant. Results: From April 2020 to August 2024, 376 patients were included in the modified intention-to-treat analysis and followed at the pre-specified time points. When comparing MF and SOC, no significant differences were captured longitudinally regardless of the severity of ARD (Common Terminology Criteria for Adverse Events Grade [G] 0-1 versus G2-3). Comparing to the baseline scores, patients reported worse pruritus at 6 months and pigmentation at 6, 12, and 24 months (p<0.0001) for the SSA. For the RISRAS, tenderness/ discomfort/ pain, itchiness and burning sensation were worse at 6 months (p<0.0001), but only itchiness was worse at 12 and 24 months (p=0.0007, p<0.0001 respectively) compared to baseline. In the subgroup analysis of patients based on severity of ARD, pigmentation was worse at all follow-up visits (p<0.0001) in both G0-1 and G2-3 cohorts. Conclusions: PROs returned to baseline at 6 months to 2 years after RT, except pigmentation and pruritus that persist regardless of the severity of ARD, necessitating confirmation with physical signs and further research to understand the pathophysiology of these chronic symptoms to guide preventative strategies. No long-term issues were identified in patients treated with MF, confirming it as a safe and effective strategy for the prevention of ARD.