It's been less than a year since the launch of Houston Methodist's HIPEC surgery program and already the hospital has become one of the only high-volume centers in the nation offering this innovative abdominal cancer treatment known as hot chemotherapy.

Few surgeons, and even fewer centers, are dedicated to performing the complex two-part procedure, still considered an emerging therapy, which often represents a patient's best hope for survival and improved quality of life.

Cytoreduction surgery immediately followed by hyperthermic intraperitoneal chemotherapy — collectively referred to as HIPEC surgery — can improve outcomes for a variety of peritoneal surface malignancies, including appendiceal and colorectal cancers, peritoneal mesothelioma and some ovarian and gastric cancers, studies show.

Doubling down on difficult-to-treat cancers

When a tumor spreads from its original location to the lining of the abdominal cavity, it can be difficult to treat using conventional therapies. Both surgery and chemotherapy have limitations which render them less effective in this specific population.

"The unique location and physiology of the peritoneum makes it easier for tumors to proliferate in this area, making complete resection difficult to achieve at times," says Dr. Amanda Arrington, a surgical oncologist and director of the Houston Methodist HIPEC surgery program. "Although cytoreductive surgery — where all of the cancer is resected — alone can palliate symptoms, it doesn't offer any true survival benefit on its own. For this reason, it has historically been considered not worth the risk."

Systemic chemotherapy, the frontline therapy for nearly all cancers, has limited therapeutic potential for patients with peritoneal malignancies thanks to the peritoneal-plasma barrier.

"For better or worse, the peritoneum does not have a good blood supply," Dr. Arrington explains. "Although this typically helps protect critical organs, when the cancer you're trying to reach is located on or inside this barrier, it makes intravenous chemotherapy significantly less effective."

Though neither surgical resection nor chemotherapy are effective treatments individually, combining them into one supersized procedure has proven surprisingly effective.

"When a successful cytoreduction surgery is followed immediately with a specialized, high-dose, warmed chemotherapy infusion, they work hand in hand and shore up each other's limitations, giving patients a treatment option that can improve both survival and quality of life," Dr. Arrington says.

How HIPEC surgery works

HIPEC infusions treat residual cancer cells left behind in the abdomen after all visible tumors and affected tissues have been removed.

A specialized bypass unit and catheters are used to infuse the patient's abdomen with a platinum-based chemotherapy solution that has been heated to approximately 120° F.

"Heating the solution to above body temperature has a synergistic effect, making the chemotherapy more potent and able to penetrate cancer cells more deeply and easily," Dr. Arrington explains. "By applying the chemotherapy locally, not systemically, we bypass the peritoneal-plasma barrier, and the side effects typically associated with systemic chemotherapy treatment are avoided or greatly reduced."

The application of heated chemotherapy has the added benefit of decreasing scar tissue that would otherwise be caused by the cytoreduction surgery.

The primary drawback of the procedure involves the patient's digestion. The bowels are likely to be impacted for weeks following the procedure due to the vigorous intra-abdominal infusion process.

Expanding indications, improving outcomes

The combination of cytoreduction surgery and HIPEC was developed more than 30 years ago to treat pseudomyxoma peritonei, a mucinous neoplasm originating in the appendix that typically fills the entire abdominal cavity. Indications for the two-stage procedure have since gradually expanded to include the majority of peritoneal surface malignancies, regardless of origin point.

"Without a doubt, cytoreduction with HIPEC has revolutionized the management of many peritoneal diseases," Dr. Arrington says. "For some conditions, this is a one-time treatment that can be completely curative. For other conditions with very few therapeutic options, it can represent the best hope to extend survival and improve recurrence-free intervals."

Current studies demonstrate outcomes improvements within the following groups:

• For pseudomyxoma peritonei, the previous five-year survival rate for patients with grade 3 disease was 6%. With HIPEC, the 10-year survival rate is 70%-80%.
• For primary peritoneal tumors/malignant mesothelioma, the previous median survival was 9-14 months. With HIPEC, the five-year survival rate is nearly 70%.
• For peritoneal carcinomatosis from colorectal cancer, the previous median survival was less than one year, with a five-year survival rate of approximately 5%. With HIPEC, the five-year survival rate (with no evidence of disease) ranges from 30%-50%.
• For peritoneal carcinomatosis from ovarian cancer, previous studies reported no survivors at the five-year mark with non-surgical care. With HIPEC, the five-year survival rate is 17%.
  

There are no formal studies or indications for peritoneal carcinomatosis originating from the liver, bile duct or pancreas.

Contraindications for the procedure include metastasis to the lymph nodes, liver or lungs; patients who have cardiac or pulmonary issues that make them not healthy enough to undergo a 6-16 hour open surgical procedure; and cancers that are too aggressive or advanced, making complications likely.

While the procedure is not new, it is still relatively rare. Only about 15 centers in the United States perform more than a dozen HIPEC surgeries a year, the definition of a high-volume center, according to the Chicago Consensus, a national group of HIPEC experts. Houston Methodist's program is already exceeding that amount.

To perform the procedure, you need a surgeon with the requisite training and experience, a specialized perfusion unit to safely administer the hot chemotherapy and a large multidisciplinary team to provide seamless care before, during and after the procedure.

"Hopefully there will be more programs like this developing in the future because more patients need access to this level of care," Dr. Arrington says. "Demand is only going to increase as more studies demonstrate improved outcomes from HIPEC surgery and indications for who can benefit continue to evolve."