Histotripsy of Liver Tumors: Patient Selection, Ethical Discussions and How We Do It

Colorectal cancer is a leading cause of cancer-related mortality, with nearly 50% of patients developing liver metastases (CRLM). Unfortunately, 85% of patients present with unresectable disease. Systemic chemotherapy offers limited survival benefits, and thus alternative therapies are urgently needed. Lo-coregional approaches such as thermal ablation and chemoembolization, while effective, have notable limitations, including invasiveness, peri-procedural risks, and required interruption of systemic treatments. Histotripsy is a novel, non-invasive method that uses focused ultrasound-induced cavitation to enable precise tumor ablation without heat or radiation. Our institution utilizes a multidisciplinary tumor board approach to evaluate patients for histotripsy, particularly in cases involving unresectable disease, complex surgical candidacy, palliative intent, or as a bridging therapy for transplantation. Early results, including preclinical data and the THERESA and #HOPE4LIVER trials, highlight its efficacy in treating liver tumors with minimal complications. Herein, we discuss institutional protocols for histotripsy including pre- and post-procedure management, and ethical discussion of current approaches. Histotripsy represents a promising, patient-centered approach for CRLM, especially for patients not eligible for traditional thera-pies, due to its favorable safety profile and compatibility with systemic treatments.