The abdomen is a complex space, filled with a variety of easily damaged and extremely important organs. When mesothelioma invades the abdominal lining, or peritoneum (paira-tin-e-um), it is therefore a very serious and hard to treat matter that may require peritoneal mesothelioma surgery.
Treating Peritoneal Mesothelioma
The peritoneum is made of two parts, the visceral and parietal peritoneum. The visceral peritoneum covers the internal organs and makes up most of the outer layer of the intestinal tract while the parietal peritoneum covers the abdominal cavity.
While both the pleural (chest) and the peritoneal (abdominal) space contain the same lining and suffer from the same cancer, the nature of the two spaces dictates that different treatment strategies must be used. The peritoneum is located in an area of soft tissues, easily accessed and pliable, where the pleura is found inside a rigid space (the rib cage) and is difficult to reach without cutting through bone. Thoracic (chest) surgery to remove the pleura almost always involves the permanent removal of at least one rib.
The peritoneal and pleural mesothelial cells are designed to provide lubricating secretions which allow the organs in each respective space to move freely. When the cells of the mesothelium malfunction due to the cancer’s progress, an overproduction of this fluid often results. This is called ascites and causes many of the symptoms discussed earlier in the diagnostic section.
Unique structures inside the abdomen make treating peritoneal mesothelioma both more difficult and, in some ways, easier than pleural mesothelioma. There are two folds of the peritoneum called the greater and the lesser omentum. These structures serve to connect the viscera and provide support for blood vessels. In most mammals, the great omentum forms a great sac, which is attached to the transverse colon and the stomach. It is loaded with fat, and covers nearly all of the intestines. The lesser omentum connects the stomach and liver and contains the hepatic vessels. the surgical procedures employed in peritoneal dictate the removal of the omentum changing the structure of the abdominal space quite dramatically.
The Mesothelioma Foundation is here to help the families and patients affected by mesothelioma. Contact our nurse practitioner for critical information about your diagnosis.
The Primary Standard of Care in Peritoneal Mesothelioma
Peritoneal mesothelioma surgery, called cytoreductive surgery, coupled with Intraperitoneal chemotherapy is now considered to be the standard of care in the treatment of peritoneal mesothelioma. Though not a curative treatment option, extended survivals have been reported by a select group of surgeons who specialize in the treatment of peritoneal mesothelioma. Cytoreductive surgery coupled with Intraperitoneal chemotherapy is now considered to be the standard of care in the treatment of peritoneal mesothelioma.
There have been no comparative mesothelioma trials of systemic versus operative procedures in peritoneal mesothelioma but the survival statistics reported in surgical series far exceed survival statistics in chemotherapy trials. With this in mind one should proceed with caution as the numbers in these trials are small, the patients are selected thus creating a bias in favor of surgery. Unfortunately, because the number of cases is reported at 250 new cases per year, a trial to provide this information would not be able to accrue the number of patients necessary to answer the question. The treatment varies with the surgeon and research is still underway to develop the optimal treatment plan.
The initial peritoneal mesothelioma surgery includes an exploration of both the peritoneum and pelvic structures. The disease is often described as salt-like or sand-like structures that can be found on all surfaces of the abdomen. This includes the length of bowel which needs to be painstakingly explored. The omentum is removed as it is usually studded with disease, and the tumor deposits are scraped off of the lining of all the visceral organs where it appears. Microscopic cells as well as small deposits of tumors are left behind and it is the expectation that a heated perfusion of chemotherapy will eradicate residual disease. Like pleural mesothelioma, imaging is not optimal and in many patients more disease than anticipated is found at the time of surgery.
The Effect of Staging on Treatment
Unlike pleural mesothelioma the typical staging system is not applicable in predicting survival in peritoneal mesothelioma. Dr. Paul Sugarbaker is credited with the creation of the peritoneal cancer index score. This staging system takes place at the time of surgery. The abdomen and pelvis are divided into 13 sections and scores are assigned based on the largest tumor found within each of these designated areas. A score is sometimes assigned prior to and following the surgical procedure.
This type of peritoneal mesothelioma surgery is referred to as a cytoreduction. Long term survival is associated with a score of CC 0 or CC1 these are considered complete resections. Scores of CC2-CC3 predict relapse and shortened survival. Grade of tumors amount of residual tumors post-surgery are factored together to assign a score.
The relative ease of access to the abdomen has many interesting benefits, however. The stomach wall can easily be entered to allow access to the abdominal space and this means that the area can support multiple debulking surgeries and inspections to keep the tumor in check. Repeated surgeries often result in the formation of scar tissue which can result in mechanical small bowel obstructions, painful strictures and digestive problems. Repeated surgery is not a standard of care but is assessed thoroughly by surgical specialists on an individual basis. Innovative techniques such as heated chemoperfusion, immunotherapy and radiation therapy are being explored. These therapies are not recommended outside of a clinical trial setting at specialized centers.
