Hepatic arterial infusion
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| Hepatic arterial infusion | |
|---|---|
| Specialty | Oncology |
Hepatic arterial infusion (HAI) is a medical procedure that delivers chemotherapy directly to the liver. The procedure, mostly used in combination with systemic chemotherapy, plays a role in the treatment of liver metastases in patients with colorectal cancer (CRC).[1] Although surgical resection remains the standard of care for these liver metastases, majority of patients have lesions that are unresectable.
The liver derives its blood supply from two sources – via the hepatic arterial circulation and the portal circulation. Liver metastases get most of their blood supply primarily from the hepatic artery, whereas the normal liver cells get their blood supply from the portal circulation.[2] This allows for chemotherapeutic drugs to be delivered directly to the cancer cells if infused into the hepatic artery. Multiple trials have compared HAI (with various chemotherapeutic agents) to systemic chemotherapy. Compared to systemic Fluoropyrimidine, HAI with Floxuridine (FUDR) had an increased response, but there was no overall increase in patient survival.[3][4][5][6][7] Efforts have been made to increase the efficacy and safety of HAI chemotherapy: when a combination of FUDR and dexamethasone was used for HAI, both response rate and median survival increased.[8] In another study, a combination of FUDR and leucovorin for HAI increased the response rate, and reduced the biliary toxicity seen with the use of FUDR alone.[9] Considering improvements in the surgical placement of the HAI pump and studies showing promising results when HAI therapy is used together with systemic oxaliplatin or irinotecan,[10][11] there is once again an increased interest in the role of HAI as a treatment option in patients with cancer, who have unresectable CRC liver metastases. However, studies recommend that this treatment modality be restricted to centers with expertise in the surgical placement of these pumps, and the technical aspects of localized chemotherapy.
Before the placement of the HAI pump, the patients undergo an arteriogram to outline the blood supply of the liver and to identify any anatomical anomalies. The procedure begins with an exploratory laparotomy to confirm the unresectable nature of the tumor, and then the gallbladder is removed by performing a cholecystectomy. This is done to prevent treatment induced cholecystitis. The distal gastroduodenal artery, the right gastric artery, and small branches supplying the stomach and duodenum are ligated. This total devascularization of the distal stomach and proximal duodenum minimizes the risk of any extra hepatic perfusion.[12] The catheter is placed at the junction of the proper and common hepatic arteries, and threaded through the gastroduodenal (mostly), or celiac artery. The catheter is fixed in this position and the pump is placed in a subcutaneous pocket. Finally, to confirm adequate placement and hepatic perfusion, and to rule out extrahepatic perfusion, a dye (fluorescein or methylene blue) is injected into the pump. After the procedure and before starting the HAI based treatment, a technetium 99m-labeled macroaggregated albumin scan is performed to again confirm adequate hepatic perfusion and no misperfusion outside of the liver.[13]
