The peritoneum is a membrane that covers the inner lining of the abdominal cavity and the organs lying in there. It helps to support these organs and contains the blood vessels and nerves that supply them. The space in the abdominal cavity covered by the peritoneum is known as the peritoneal cavity (Figure 1).
Figure 1: Peritoneal cavity
Metastasis occurs when cancer spreads from its original site to other parts of the body. Peritoneal metastases refer to cancer that has spread to the peritoneum from other organs. When cancer spreads from other organs, it is considered advanced and denote Stage IV disease in most cases.
Cancers that develop from the peritoneum itself, such as primary Peritoneal Cancer or Peritoneal Mesothelioma, are very rare.
Complications related to Peritoneal Metastases:
Some common symptoms include:
Figure 2: Ascites due to Peritoneal Metastasis
Consult your doctor if you experience these symptoms.
The diagnosis of Peritoneal Cancer can be difficult. Imaging (such as CT or MRI scans), needle drainage of ascitic fluid for analysis, keyhole surgery, or a combination of these may be required to confirm the diagnosis of Peritoneal Metastases.
Patients who suffer from cancers mainly of abdominal origins such as gastric (stomach), ovarian, colorectal, appendix and pancreas cancers are at risk of developing Peritoneal Metastases. Less commonly, other cancers can also spread to the peritoneum.
Peritoneal Metastases develop as cancer spreads. Presently, besides controlling the original cancer, there is little more that can be done to prevent Peritoneal Metastases. Patients who experience the symptoms mentioned above should seek medical assistance for a thorough evaluation.
Peritoneal Metastasis is difficult to treat and is best managed by a multi-disciplinary team that includes surgeons and medical oncologists.
Chemotherapy drugs given intravenously or sometimes in combination with oral tablets circulate through the whole body. This type of treatment is suitable for cancers that have metastasised to multiple parts of the body.
CRS is an extensive surgery that removes all visible cancers within the abdominal cavity. At the end of CRS, a heated chemotherapy solution is applied in the peritoneal cavity to destroy the remaining cancer cells that cannot be seen with the naked eye.
IP chemotherapy (Figure 3) is injected into the peritoneal cavity via an intraperitoneal port that is inserted via keyhole surgery. The port is buried under the skin and connected to a catheter that enters the peritoneal space.
Figure 3: Set-up of IP Chemotherapy
PIPAC (Figure 4) is a novel method of delivering chemotherapy directly into the peritoneal cavity in an aerosol form. It utilises the physical properties of pressurized gas to distribute the drug evenly and deeply. This allows greater penetration of the drug into the cancer cells, with reduced systemic side effects of the chemotherapy agent. PIPAC is performed as a short and simple laparoscopic (keyhole) surgery. Under general anaesthesia, small instruments will be placed into the abdomen. A micro-pump will deliver the chemotherapy drug into the peritoneal cavity as an aerosol. At the end of the procedure, any residual gas within the peritoneal cavity will be removed.
Currently, PIPAC is a minimally-invasive palliative procedure that aims to prolong survival and preserve quality of life. Due to the low dosage applied, PIPAC can be combined with systemic palliative chemotherapy and has minimal organ toxicity. This procedure can be repeated at intervals of six weeks to three months.
Figure 4: Set-up of Pressurised Intra-Peritoneal Aerosol Chemotherapy (PIPAC)
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