Hepatic artery infusion (HAI) pumps were first introduced as an alternative to traditional chemotherapy delivery nearly 30 years ago. Yet, despite several clinical studies proving the effectiveness of HAI pumps in treating colorectal patients with inoperable liver metastases, very few cancer centers have adopted this as a treatment method.
In a recent interview, Oncology Times spoke with Alexandra Gangi, MD, Director of the Gastrointestinal Tumor Program and Associate Professor of Surgery at Cedars-Sinai Cancer Center, and Cristina Ferrone, MD, Chair of the Department of Surgery and a care specialist for patients with complex hepato-pancreato-biliary disorders at Cedars-Sinai, to discuss the risks and benefits of HAI pumps, as well as the critical need to make this treatment option more widely available.
"There has been limited, large-volume, prospective, randomized data suggesting that the HAI pump is superior to systemic therapy alone," the researchers noted. Gangi and Ferrone promoted this targeted chemotherapy delivery system, which can be used in combination with systemic therapy.
According to the Centers for Disease Control, colorectal cancer was the cause of approximately 52,000 deaths nationwide, making it the second-leading cause of cancer-related death. Of the 150,000 plus patients diagnosed with colorectal cancer every year in the U.S., approximately 25 percent will experience liver metastases, which can be deadly, especially if inoperable.
Hepatic Arterial System
"The liver is the most common site of metastasis in patients with colorectal cancer due to the fact that the liver receives blood from the portal vein, which it filters," Gangi and Ferrone noted. "The portal vein drains the bowel and colon via the superior mesenteric vein, which drains into the portal vein and into the liver."
Using the hepatic arterial system, which is supported by the superior mesenteric vein, the HAI pump is able to directly attack cancer in the liver. For colorectal patients with inoperable liver tumors, this system provides hope and can significantly improve quality of life, allowing physicians to administer higher doses of the appropriate chemotherapeutic agents without exposing the patient to systemic toxicities associated with these agents-nausea, fatigue, fevers, etc. In fact, clinical research has shown that more than half of patients, around 60 percent, receiving this liver-directed therapy will become eligible for curative surgery. While surgery is the goal, it is also a means to the end.
Unlike oral or intravenous delivery methods for chemotherapy, the HAI pump must be surgically placed beneath the skin outside the abdominal cavity. Attached to the pump is tubing that is inserted into the abdominal cavity and directed to the gastroduodenal artery, which feeds into the hepatic artery and supplies blood to the liver. To ensure the chemotherapy treatment is directly targeting the liver, surgeons will block blood flow from the gastroduodenal artery to the small intestine. Before finalizing surgery, dye is injected into the pump to test that the blockages were successful in directing treatment to the intended destination-the liver.
"In addition, postoperatively, the patient has a nuclear medicine perfusion scan to evaluate if there is flow outside of the liver," Gangi and Ferrone explained. "If there is concern for flow outside the liver, the patient is then evaluated by interventional radiology with an angiogram and any vessels that don't appear to be blocked off are then blocked off."
Following surgery, the pump needs to be refilled every 2 weeks. Due to the pump's soft center, the internal reservoir can be accessed through the skin via a syringe. The researchers compared the sensation to "having an IV placed where you may feel a pin prick through the skin." When it is determined that a patient is no longer utilizing the pump or there are no plans to utilize the pump in the patient's future care, they are taken back into the operating room where an incision is made to remove the pump from the skin. Then, the catheter draining the pump into the gastroduodenal artery is tied off and placed in the abdominal cavity.
Presently, HAI pumps are used to treat patients with cholangiocarcinoma, a primary biliary tumor, and colorectal patients with inoperable liver metastases. However, this therapy option is not yet the current standard of care for either disease.
Other cancers that primarily metastasize to the liver, such as gastric cancer, pancreatic cancer, melanoma, and sarcoma, are more difficult to treat. Therefore, HAI pumps are not thought to benefit these patients. Gangi and Ferrone encourage patients who may benefit from HAI pump therapy to seek a participating cancer center and schedule a consultation to determine eligibility for this treatment option.
"We hope that it will provide an additional treatment option for certain patients who have limited options at the time of evaluation," the researchers concluded.
Elizabeth Galamba is a contributing writer.