What is Peritoneal Mesothelioma? Peritonectomy, Cytoreductive Surgery, and HIPEC

What is Peritoneal Mesothelioma?

The peritoneum is an organ made up of a two-layered membrane that covers the abdominal cavity and the organs inside it. One of the peritoneal cancers is peritoneal mesothelioma, which is a rare cancer. The membrane called peritoneum originates from the body’s mesothelial layer. The mesothelial layer surrounding the lungs is called pleura, while the one surrounding the heart is called pericardium. The most common cause of mesothelial layer cancer is the inhalation of small asbestos fibers. Therefore, the pleural form of cancer is the most common; however, these fibers can also be swallowed with phlegm. Also, they can cause tissue damage that leads to peritoneal mesothelioma by migrating from the chest cavity to the abdominal cavity.

What are the types of peritoneal cancer?

Like many solid organ cancers, peritoneal cancers can be primary (originating in the peritoneum) or secondary (metastatic). Here, primary and secondary refer to where the cancer originated. The names do not indicate how severe the cancer is.

Primary Peritoneal Cancers

Primary peritoneal cancer begins and develops in peritoneal cells. When we talk about primary peritoneal cancer, the first thing that comes to mind is primary peritoneal carcinomatosis, which is closely related to epithelial ovarian cancer. They are both treated similarly and have a similar perspective.

Peritoneal mesothelioma, which is the subject of our article, is a rare type of primary peritoneal cancer.

Secondary Peritoneal Cancers

Secondary peritoneal cancer usually begins in another organ in the abdomen and then spreads to the peritoneum (metastasizes).

Secondary peritoneal cancer can start from the following organs:

• Ovaries
• Fallopian tubes
• Bladder
• Stomach
• Small intestine
• Colon
• Rectum

Secondary peritoneal cancer can affect both males and females and is more common than primary peritoneal cancer.

For example, it is known that 15% to 20% of people with colorectal cancer will develop peritoneal metastases. Approximately 10% to 15% of people with stomach cancer develop metastases in the peritoneum.

When cancer metastasizes from its original location, the new site will have the same type of cancer cells as the initial site.

Peritoneal Mesothelioma Treatment

Survival rates for peritoneal mesothelioma tend to be poor. It is known that approximately one in four people diagnosed with this condition will live for three years or more. A suitable treatment approach planned by experienced hands can extend life expectancy. If peritoneal mesothelioma is diagnosed early, there is a relatively limited chance of a cure (complete recovery). The best way to achieve remission (extend the disease-free period) is to remove cancerous tissues through surgical procedures that are either complete or nearly complete.

What is Peritonectomy?

Peritonectomy is a form of cytoreductive surgery. Cytoreductive surgery is any surgical procedure that eliminates cancerous tissue. The term peritonectomy specifically refers to the removal of the peritoneum. The surgery can also remove organ pieces with cancerous tissue. The affected organs are the small intestine, large intestine, gallbladder, liver, stomach, pancreas, and spleen.

1. “Surgery is mostly aimed at relieving symptoms and complaints. Although it is not always possible to completely remove cancer with surgery, it can slow down the progression and provide remission. Surgery is usually combined with chemotherapy to increase the likelihood of remission and reduce the risk of recurrence after surgery. This combination can eliminate cancer cells that the surgeon cannot safely remove or that are too small to be removed during surgery.

What is Hyperthermic Intraperitoneal Chemotherapy?

For peritoneal mesothelioma, Hyperthermic Intraperitoneal Chemotherapy (HIPEC) is often used after the surgical procedure during surgery. HIPEC is a relatively innovative chemotherapy method that involves injecting heated chemotherapy drugs directly into the abdominal cavity. This is different from traditional chemotherapy, which administers drugs intravenously (through the veins) and allows the drugs to circulate throughout the entire body.

HIPEC for colon, rectum, ovarian, gastric, and peritoneal cancer involves intraperitoneal administration of hot chemotherapy.”

2. “It has been proven that HIPEC is more effective than standard chemotherapy in the treatment of peritoneal mesothelioma. Some studies have found that treatment with HIPEC gives patients significantly longer survival times. This is a great success in treating a disease that was previously very difficult to manage. The increased survival time after HIPEC is associated with the epithelial subtype of mesothelioma.

The Importance of Peritoneal Cancer Index

The peritoneal cancer index (PCI) is used to assess the rate of peritoneal cancer throughout the peritoneal cavity. For this purpose, the peritoneal cavity is divided into 13 well-defined regions (see the figure below). In each of the 13 regions, the size of the largest tumor nodule is measured. If no tumor is visualized, a score of “0” is given for that region. If the largest tumor nodule is less than 0.5 cm, the score is “1”. For tumors measuring between 0.5 cm and 5 cm, the score is “2”. For lesions larger than 5 cm, the score is “3”. If there is layering or the merging of multiple small tumor nodules, the score is “3”. The peritoneal cancer index is calculated by adding the scores of all 13 regions, with a maximum of 39 (13 × 3) points.

As the peritoneal cancer index decreases, disease-free survival and overall survival increase. Generally, aggressive treatments are not recommended for patients with a high PCI score.

HIPEC or Standard Cytoreductive Surgery?

The largest multi-institutional registry combining retrospective data on patients with peritoneal mesothelioma (PM) treated with cytoreductive surgery (CRS) and HIPEC from 29 clinical centers worldwide included 405 PM patients; various intraperitoneal chemotherapeutic agents were used during HIPEC, including cisplatin, mitomycin C, and doxorubicin. Patients treated with HIPEC had a median overall survival of 53 months, and one-, three-, and five-year survival rates were 81%, 60%, and 47%, respectively. Prognostic factors associated with increased survival in multivariable analysis included the epithelioid histologic subtype, absence of lymph node metastases, complete or nearly complete resection, and the use of HIPEC.”

What are the benefits of peritonectomy?

Peritonectomy and HIPEC have several goals. These procedures tend to be palliative, meaning they aim to reduce symptoms, extend survival, and achieve the best chance of long-term remission. Improving peritoneal mesothelioma is a realistic goal; individuals with less tumor tissue now have a better chance for the combination of peritonectomy and HIPEC, which results in long-term remission.

For most mesothelioma patients, this surgery is used to extend life. The benefit of peritonectomy for patients with advanced cancer is to reduce symptoms and complaints. Removing or reducing tumors in the abdomen can reduce pain and swelling, making the patient feel more comfortable.

Risks and complications

Peritonectomy and subsequent HIPEC are major surgeries. Although less risky than radical surgeries used to treat pleural mesothelioma, they can still have significant complications. Older patients or those with complex medical issues are more likely to experience postoperative complications.

Possible postoperative complications include fistulas (perforation) from the intestines, leakage from where the intestines are sewn together, excessive bleeding, and intra-abdominal infection. Other complications are the same as those seen in any major surgery, including blood clots and infections. Unfortunately, it is possible for a patient to struggle to recover from this surgery, only to have the cancer recur shortly after.

Organ damage and ostomy requirement

Whenever there is surgery in the abdominal cavity, there is always a risk of small injuries to the intestines or urinary tract. If surgical repair is not possible, or if there is significant tumor involvement inside the abdomen, a procedure called ostomy may be necessary. A stoma is a surgical practice that diverts the digestive or urinary tract out of the body. With this procedure, an opening called a stoma is created, which connects the small intestine, colon, or ureter to the outside of the body, bypassing the normal routes for waste to exit the body.

Ostomies are typically done when the bladder or intestines are unable to function normally due to tumor involvement. In rare cases, organ damage can occur as a complication of surgery. This is not a common complication, but any abdominal surgery, including cytoreductive surgery, can cause damage that requires ostomy. The stoma can be permanent or temporary to allow for the affected tissue to heal.

Living with an ostomy brings many challenges. Patients need an ostomy bag to collect feces or urine. There is no valve to cut off the flow of the stoma, and the patient cannot control the passage of waste from their body. Expert ostomy nurses are an invaluable source for providing a management plan that includes problem-solving for any issues that arise. Coping with complex body image changes can be emotionally challenging. These changes can be temporary or permanent. If stomas need to be closed or are planned to be closed, another surgery will be required.

The recovery from cytoreductive surgery plus HIPEC varies depending on the patient. Younger, healthier patients and those in earlier stages of cancer typically recover more quickly and with fewer complications. If there are any complications, patients should stay in the hospital following the surgery and HIPEC chemotherapy. After the surgery, patients can receive intravenous medications and fluids. Typically, a nasogastric tube is present to empty the stomach until normal bowel function returns. The goal is to return to oral feeding as soon as possible. Having a nutrition specialist can be very helpful in providing new diet recommendations. After patients go home, they will be in modified activity until they are fully healed.