The prognostic value of acneiform rash grade in metastatic colorectal cancer patients treated with EGFR inhibitors.

Abstract

e15599 Background: Epidermal growth factor receptor inhibitors (EGFRis), such as cetuximab and panitumumab, are widely used in the treatment of metastatic colorectal cancer (mCRC). These therapies are often associated with cutaneous toxicities, most notably acneiform eruptions, which occur in up to 90% of patients. Prior studies suggest that acneiform eruptions correlate with improved prognosis, however the relationship between rash grade and patient survival outcomes has yet to be fully characterized. This study aims to evaluate the association between rash grade, progression-free survival (PFS), and overall survival (OS) in mCRC patients treated with EGFRis. Methods: This retrospective analysis included mCRC patients who received cetuximab or panitumumab between 2020 and 2023 at a single tertiary care cancer center. Patient charts were reviewed to document rash onset, duration, severity, management and patient outcomes. PFS and OS were analyzed using Kaplan-Meier methods, with hazard ratios (HR) calculated using Cox proportional hazards models. Results: A total of 258 patients were included in the analysis, with 28.3% receiving cetuximab. The mean age was 56.9 years, and 71.3% of patients were White. Rash grades were distributed as follows: grade 0 (25.6%), grade 1 (32.9%), grade 2 (39.5%), and grade 3 (1.9%). Median PFS was 91 days for grade 0, 166 days for grade 1, 153 days for grade 2, and 215 days for grade 3 (p < 0.001). Pairwise comparisons demonstrated significant differences in PFS between all rash grades versus no rash (p-values < 0.05). Higher-grade rashes were associated with a lower risk of progression (HR = 0.592, p < 0.001). Median OS was 204 days for grade 0, 539 days for grade 1, 561 days for grade 2, and 544 days for grade 3 (p < 0.001). Pairwise comparisons indicated significant differences in OS for patients with grade 1 and 2 rashes compared to those with no rash (p-values < 0.05). Higher-grade rashes were associated with a reduced risk of death (HR = 0.620, p < 0.001). Conclusions: In this study, we find that higher-grade acneiform eruptions were associated with a significantly lower risk of both disease progression and death. Specifically, patients with higher-grade rashes had an approximately 40% reduction in the risk of both progression and death for each increase in rash grade. These findings suggest that rash grade may serve as a prognostic indicator of treatment outcomes, offering insight into patient management strategies and guiding clinical decision-making in EGFRi therapy.