P-363 Skin rash as a predictor of tumor response to EGFR inhibitors in advanced colorectal cancer

The epidermal growth factor receptor (EGFR) is overexpressed in 70-80% of patients with advanced colorectal cancer. development antibodies that target this receptor, cetuximab and panitumumab, lead to an increase overall survival setting. During therapy EGFR inhibitors, the most common toxicity acneiform rash, may represent early biomarker tumor shrinkage might predict effectiveness inhibitors. aim study assess predictive value skin rash terms response (OS) cancer treated panitumumab. We conducted a retrospective receiving EGRF inhibitors or panitumumab from January 2013 2023. Using Cox regression, role on OS, progression rate were obtained. A total 101 analyzed: median age was 65 years, 59% male, 91% received 71% developed rash. Median OS 31.1 months. occurrence associated reduced risk death (HR 0.25, 95% CI 0.15-0.43, P < 0.00001) increased chance (70% vs 15%, p=0.24). All 6 who had complete toxicity. Skin also for 0.27, 0.15-0-48, 0.00001). introduction setting provided OS. toxicities are adverse events good predictor therapy. Though rarely life-threatening, these impact quality life, patient infections, inconsistent EGFRI administration, all which affect clinical outcomes. promptly treatment essential avoid delays interruption