Cancers located in the abdomen — including colorectal cancer, appendix cancer, gastric cancer, and gynecologic cancers such as certain types of ovarian cancer — can be difficult to treat with traditional chemotherapy when the tumors spread beyond the organ in which they originated.
Surgeons do their best to remove all of the tumor when they operate on cancers that have spread throughout the abdomen, but the risk of recurrence is high in patients with these advanced cancers. A specialized procedure called cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS/HIPEC), in which heated chemotherapy drugs are pumped directly into a patient’s abdominal cavity after surgery, helps to eradicate any remaining cancer cells.
“It takes tens of thousands of cancer cells to be able to see a tumor with the naked eye, so if there are still small groups of invisible cells floating around in the abdomen, the idea is to deliver a high dose of chemotherapy to kill these remaining cells ,” says University of Colorado Cancer Center member Steven Ahrendt, MD, professor of surgical oncology at the CU Department of Surgery. “We can usually achieve a concentration that’s 20 times higher in these small tumors than we could get through an IV with traditional systemic therapy.”
The HIPEC advantage
First used in 1980 and perfected in the intervening decades, HIPEC is a specific therapy for cancers that have spread into the abdominal or peritoneal cavity. Once the fluid is pumped into the abdomen, surgeons physically rock the patient back and forth every so often for up to two hours to ensure even distribution.
For patients, HIPEC has the advantage of being a single treatment done in the operating room, versus multiple treatments over several days or weeks. In addition to offering a higher dose of chemotherapy than patients could receive intravenously, the HIPEC treatment also keeps 90% of the drug in the abdominal cavity, reducing toxic effects on the rest of the body. Ahrendt helped expand the technique at the CU Cancer Center in 2017, when he arrived from the University of Pittsburgh.
“At that time, Pittsburgh was one of, if not the busiest departments in the world doing the procedure,” he says. “When I had the opportunity to move here, many patients were leaving Denver to have HIPEC elsewhere. The program has really grown since I’ve been here.”
How it works
Abdominal surgery involving HIPEC generally happens in three stages, Ahrendt says. The first and most critical part of CRS/HIPEC is removing all the visible cancer. For the most part, he says, if any visible cancer is left behind, patients fare no better than if they avoided surgery and remained on traditional chemotherapy. Part two is the HIPEC, and part three is any reconstruction that needs to be performed.
“The perfusion apparatus, similar to a heart-lung machine, has a reservoir that we put fluid or perfusate in,” Ahrendt says. “The perfusate goes through a heating coil, then into the abdomen, then out through a separate channel where it is then reheated and recirculated. The chemotherapy agent is added to the perfusate and is specific to the cancer being treated. The temperature in the surface of the abdomen is maintained between 41 42 degrees Celsius. At a high temperature, the cytotoxicity, or the drug’s ability to kill cells, is higher.”
HIPEC is typically performed during traditional open surgery, though it can be performed laparoscopically as well.
“For patients who have limited disease in their abdomen, which is less than 5% of patients, we can remove the disease with a minimally invasive technique, and we can do the HIPEC through a limited incision,” Ahrendt says.
A new standard of care
Every patient’s situation is different, but for those in whom HIPEC is an option, outcomes tend to be better when the treatment is used.
“The abdomen is a big space, and cancer can spread throughout the abdomen and affect any part of the abdomen or the surface of the abdomen,” Ahrendt says. “The goal in every patient is to get all the visible cancer out, which is what we can achieve as surgeons. The HIPEC may lower the risk of the cancer recurring within the abdomen. There’s been a bit of a barrier in it getting widespread acceptance, but for most tertiary care centers in the U.S., it’s become the standard of care, and we endorse it in the right patient population."