Hepatic chemoembolization: clinical and experimental correlation

Chemoembolization has become the preferred treatment for patients with inop erable, hypervascular hepatic malignancies in the Far East, but controversi al elsewhere. In vivo microscopy in addition to other experimental procedur es are used in this presentation to better understand the mechanisms involv ed in chemoembolization, In chemoembolization Lipiodol acts as a contrast m aterial, a vehicle for chemotherapy and an embolic agent. Although not opti mal, Lipiodol injected into the hepatic artery, traverses the peribiliary p lexus to the portal veins resulting in a dual embolization, Chemoembolizati on creates ischemia, slows arterial flow and increases the contact time bet ween the infusate and the neoplasms, increasing the tumor cell kill. Howeve r, the vascular occlusion also produces infarction and fibrosis compounding the already existing cirrhosis frequently associated with hepatocellular c arcinoma. Lipiodol/ethanol (3:1) injected into the segmental or lobar hepatic artery supplying the neoplasm also gains access to the associated portal venous br anches causing focal ablation, This preoperative approach is easier to perf orm than direct portal vein occlusion, with less parenchymal damage and com parable hypertrophy of the remnant liver frequently necessary for adequate hepatic function following resection. Polymer-drug conjugates, e.g. PG-TXL, have considerable potential for intra -arterial delivery especially with the dramatic increase in concentration o f the drug in the tumor and its efficacy. Using in vivo microscopy especial ly with green fluorescent protein (GFP) gene as an efficient and non-toxic tumor cell marker, the events leading to hepatic metastases can be document ed which will serve to better evaluate these varied techniques of chemoembo lization.