Heated Intraperitoneal Chemotherapy

Heated intraperitoneal chemotherapy (HIPEC) is a recently developed strategy for using chemotherapy to treat peritoneal mesothelioma. Instead of delivering chemotherapy drugs to the patient intravenously, the traditional method, HIPEC injects heated drugs directly into the abdominal cavity to shrink tumors and kill cancer cells. HIPEC is most often used as part of a multi-modal approach to treating mesothelioma. first the patient undergoes surgery to remove as much of the tumors as possible.

Traditionally, chemotherapy has been successful for treating peritoneal mesothelioma. However, HIPEC has proven one of the most effective treatments for this cancer, greatly improving survival rates.

What is HIPEC?

Typically, chemotherapy is a highly effective cancer treatment. Chemotherapy uses one or more drugs that target and kill fast-growing cells, like cancer cells. For many patients it effectively shrinks tumor, In some cases, it even leads to remission. Traditionally, chemotherapy drugs are administered intravenously, entering the drug stream directly and then circulating through the body. This method kills cancer cells, but also damages many healthy cells in the process.

HIPEC is more specific than the traditional administration of chemotherapy drugs. Instead of simply injecting drugs into bloodstream, the drugs are injected directly into the abdomen, specifically targeting peritoneal tumors. Before being injected, the drugs are heated the abdominal cavity is essentially bathed in the chemotherapy drugs.

The Procedure

HIPEC begins with cytoreductive surgery, which removes as much of the tumors as possible. This is an important step because chemotherapy drugs cannot penetrate to the center of tumors. For chemotherapy to be effective, the bulk of the tumors must first be removed. Once most of the tumor tissue is removed, the bath of chemotherapy drugs can circulate, killing cancerous cells that remain in the abdominal cavity. For some patients, tumors may be too numerous to remove with surgery. In these cases, chemotherapy will not be as effective.

After surgery, the next step is the heated chemotherapy bath. Even if the surgery removed all visible tumors, cancer cells may still be left in the abdomen. The goal of this second step kill the remaining cancer cells. Catheters are inserted into the abdomen. These catheters are connected to a machine that a solution of chemotherapy drugs. The machine then pumps the drugs through the catheters and into the abdominal cavity.

The bath is monitored carefully to maintain a temperature of 105 degrees or a little higher. This temperature is key because cancer cells begin to die in temperatures of 105. However, healthy cells tolerate temperatures up to approximately 110 degrees. After the solution has circulated through the abdominal cavity, outflow catheters send it back to the machine. The entire process usually takes a couple of hours.

Chemotherapy Drugs Used

There are many drug options for HIPEC. However, research has shown that a combination of drugs more effectively extends life expectancy than using a single drug. Researchers are also attempting to determine which specific drugs are most effective. The most common chemotherapy drugs used effectively in HIPEC procedures are cisplatin, carboplatin, gemcitabine, pemetrexed, and doxorubicin.

Recovery

Patients undergoing HIPEC will usually remain in the hospital for about a week. However, complete recovery from HIPEC can take several months. Complete recovery includes healed surgery incisions and an absence of infection. The chemotherapy drugs will cause the most side effects, the most common being fatigue. It can take several months to regain normal energy levels.

How HIPEC Affects Survival Rates

HIPEC has had a significant effect on the survival of patients with peritoneal mesothelioma. In some cases, patients live five or more years after the procedure. This is a significant improvement over more traditional treatments. One large HIPEC study examined over 400 patients and found the median survival time was between four and five years. One patient in the study was alive 19 years later and was considered cured.

Patients Eligible for HIPEC

Not all patients with peritoneal mesothelioma will be eligible for this treatment. First,the patient must be healthy enough for surgery. HIPEC is only effective with surgery as the first step. Another disqualifying factor is extensive spread of the cancer. If tumors have spread outside the abdominal cavity, the procedure will have little effect on patient survival. Healthy patients with no serious comorbid conditions like heart disease, are excellent candidates for HIPEC treatment.

Benefits and Risks

The most important benefit of undergoing HIPEC is improved survival time. After this treatment, most patients will have an extended life expectancy. When compared to traditional chemotherapy, HIPEC causes fewer, less severe side effects. It also allows for a safer delivery method of more concentrated chemotherapy drugs. HIPEC also improves quality of life for patients. Once the side effects have dissipated, patients experience reduced cancer symptoms, particularly pain.

There are risks associated with any surgery and chemotherapy. Fifteen percent of patients will experience abdominal wall morbidity complications, including infections at the incision sites. About fifteen percent of patients will experience intra-abdominal complications like fistulas, abscesses, or gastrointestinal leaks. Systemic complications caused by the chemotherapy drugs are also possible, including infections, suppression of bone marrow, and pulmonary problems.

HIPEC and Pleural Mesothelioma

HIPEC has been used to treat peritoneal mesothelioma for some time. Now, some specialists are adapting the technique for pleural mesothelioma. The practice, called heated intrapleural chemotherapy, is controversial. While some studies show extended life expectancy, others find the effects of the chest cavity procedure similar to intravenous chemotherapy. Because there so many blood vessels in the chest cavity, they absorb the chemotherapy drugs from the heated bath. These drugs then circulate with the blood, spreading them through the entire body, just as with intravenous chemotherapy. Still, some specialists have found success with the procedure, extending patient survival by years.

Research into improving HIPEC, is expected to continue. Experts and researchers should continue to advance the treatment strategy, helping more patients live longer after a mesothelioma diagnosis.