162P Personalized circulating tumor DNA as a predictor of pathologic response in neoadjuvant treatment of resectable melanoma

Patients with resectable stage III-IV melanoma are at high recurrence risk following surgical excision. Neoadjuvant therapy (NEO) with immune checkpoint inhibition (ICI) improves event-free survival and may allow for pathologic treatment response assessment with potential adjuvant therapy de-escalation. Identification of a biomarker correlated with tumor response could facilitate individualized therapeutic decision making. This study investigates the utility of circulating tumor DNA (ctDNA) as a predictive biomarker of pathologic response in melanoma treated with NEO ICI.