Introduction
The peritoneum is a membrane that lines the abdominal cavity. It is extremely complex. It has two layers, with the outer layer, called the parietal peritoneum, attached to the walls of the abdomen and the pelvis. The inner layer, called the visceral peritoneum, encircles some organs of the abdomen. The space between the two layers, called the peritoneal cavity, contains a fluid. This fluid provides lubrication to the layers and supports them to slide across each other. However, this fluid also facilitates the spread of peritoneal cancers along the peritoneal surface.
What Are Peritoneal Surface Malignancies?
Peritoneal surface malignancy refers to the invasion of malignant cells by serous membranes lining the abdominal cavity, viscera, and coelom in amniotes. They are of two types, primary and secondary peritoneal cancers. Primary mesothelioma arises from a de novo origin of cancer of the abdominal mesothelium. On the other hand, secondary peritoneal cancer arises from the spread of tumor cells from other sites of the peritoneal cavity. Based on histology, primary cancer is again divided into two types.
Where Do Peritoneal Tumors Start?
Most of the peritoneal cancers originate from some other part of the body. Cancers of the ovaries, stomach, rectum, colon, appendix, and ovaries frequently spread to the peritoneum in the surrounding area. However, cancers that originate from other parts of the body outside the abdomen, like breast cancer, can spread to the peritoneum. Recurrent episodes of abdominal cancer frequently appear as peritoneal cancer. Diagnosing primary peritoneal cancer can be challenging and is often misdiagnosed as adenocarcinoma of unknown primary origin.
What Is Hyperthermic Intraperitoneal Chemotherapy?
The most extensively researched modality after the cytoreductive surgery (CRS) approach with a reliable and clinically improved result is hyperthermic intraperitoneal chemotherapy (HIPEC). This is a heated locoregional chemotherapy treatment, which makes the chemotherapy more cytotoxic and penetrates the tumor cells. When chemotherapy is used for a particular region in the body, it is called locoregional chemotherapy. HIPEC is usually given to expose bowel resection lines to the chemotherapy in an attempt to reduce the risk of anastomotic recurrence, following CRS but prior to any digestive reconstruction or diversion.
How Does Hyperthermia Intraperitoneal Chemotherapy Work?
The goal of HIPEC is to completely eliminate any remaining microscopic disease from the peritoneal surface. Moderate hyperthermia above 40 degrees Celcius has a direct anti-tumor effect by enhancing the cytotoxicity (toxicity to the cancerous cells) of certain chemotherapy drugs and increasing its penetration capacity into the tumor nodules. By offering a continuous circuit with a pump and heat exchanger, along with constant temperature monitoring, a constant hyperthermia is maintained in HIPEC. Temperature probes are inserted into the circuit and intraperitoneal cavity at several locations during the procedure, including the bladder, liver, mesentery, heat generator, and input and outflow drains.
How Is Hyperthermia Intraperitoneal Chemotherapy Done?
HIPEC is generally used in two ways. They include:
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Open Abdomen Technique: This technique was first described by Sugarbaker. Following a surgical cytoreduction, four closed suction drains and a Tenchoff catheter are inserted through the abdomen walls and sutured to the skin. In order to monitor the temperature intraperitoneally, the temperature probes are fastened to the skin's border. In order to preserve open space within the abdominal cavity, the skin margins at the level of the abdominal incisions are suspended till the self-retaining retractor by using a monofilament. A plastic sheet is put into this suture to stop the chemotherapy fluid from leaking out. Throughout the surgery, all anatomical structures are uniformly exposed to heat and chemotherapy due to the surgeon's continuous control of the perfusion.
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Closed Abdomen Technique: The placement of thermal catheters and probes is identical; however, to enable perfusion in a closed circuit, the skin borders of the laparotomy are securely sutured. During the infusion, the surgeon manually shakes the abdomen wall to ensure even heat distribution. This method of creating the circuit uses a larger volume of perfusate, and it also results in higher abdominal pressure during the perfusion, which helps the medication penetrate the tissue. The abdomen is opened again after infusion in order to remove the perfusate and prepare the anastomosis. Because there is less heat loss with this method, hyperthermia may be maintained quickly.
What Are the Benefits of Hyperthermic Intraperitoneal Chemotherapy?
Studies have shown that the adjuvant use of HIPEC with surgery has been more successful in treating gastrointestinal malignancies that have metastasized to the peritoneal surface. When combined with tumor excision, HIPEC can help patients who would otherwise have few or no options survive longer and live better. Significant pain reduction was also achieved by this approach.
There are many reasons why cytoreductive surgery must be done along with HIPEC. A peritoneal malignancy may resurface quickly and may even worsen if surgery is done without HIPEC. It can be due to the fibrin trapping of microscopic intraabdominal residual disease. Adhesions establish obstacles with an uneven medication distribution in patients undergoing HIPEC post-surgical recovery. This could even result in the failure of the therapy.
What Are the Complications of Individual Intraperitoneal Chemotherapy?
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Mitomycin C: Myelosuppression is the most common toxicity of Mitomycin C. A condition where the bone marrow is not able to produce a sufficient amount of blood cells or platelets is called myelosuppression. It increases the risk of infections, anemia, or causes other bleeding issues.
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Platinums: While large doses of Cisplatin can be nephrotoxic, there is some indication that high doses of intraperitoneal Oxaliplatin can predispose patients to bleeding issues and mild liver toxicity.
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Irinotecan: Another intraperitoneal chemotherapeutic drug for HIPEC that has been investigated is Irinotecan. Studies using Oxaliplatin and Irinotecan for HIPEC showed no difference in complications. However, better survival was observed with Oxaliplatin. This revealed why Irinotecan could not be a safe intraperitoneal chemotherapy agent.
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Melphalan: Another medication called Melphalan has been used in some instances in place of conventional intraperitoneal chemotherapy drugs, with some success and tolerable morbidity and fatality rates. Studies reveal it can be opted as a second-line chemotherapeutic agent in HIPEC.
Conclusion
It has been widely accepted that a combination of cytoreductive surgery along HIPEC is a promising treatment in the management of peritoneal surface malignancies. It reduces the recurrence rates and gives the complete benefit of the surgery. Moreover, it increases the overall survival of the patient after the treatment.
