Abdominal cavity and peritoneum:
The abdominal cavity is the largest hollow space of the body. Its upper boundary is the diaphragm, a sheet of muscle and connective tissue that separates it from the chest cavity; its lower boundary is the upper plane of the pelvic cavity. Vertically it is enclosed by the vertebral column and the abdominal and other muscles.
The abdominal cavity contains the greater part of the digestive tract (stomach, the small and large intestines), the liver and pancreas, the spleen, the kidneys, and the adrenal glands located above the kidneys. Below it is continuous with the pevic cavity which contains the urinary bladder, the prostate, uterus and vagina and the rectum( terminal part of the large intestine)
Figure 1: Abdominal Cavity
The abdominal cavity is lined by the peritoneum, a membrane that covers not only the inside wall of the cavity (parietal peritoneum) but also every organ or structure contained in it (visceral peritoneum). . Its surface is as large as the skin surface, 2 square meters.
The space between the visceral and parietal peritoneum, the peritoneal cavity, normally contains a small amount of serous fluid that permits free movement of the viscera (organs), particularly of the intestines, inside the peritoneal cavity.
Figure 2: The Peritoneal Cavity
What is peritoneal cancer?
Peritoneal cancer means the presence of cancer cells on the peritoneum. The tumor deposits are usually small , the size of rice grains. At times the deposits can be large even upto 5 cm in size.
Peritoneal cancer is primary when the tumro arises from the peritoneum itself (primary peritoneal carcinomatoses). It is secondary when tumor from other sites spreads to the peritoneum. Secondary spread is more commonAlmost any cancer can spread to the peritoneum, but this is more commonly seen in tumors of the abdominal cavity like such as tumors of the stomach, pancreas, large bowel (colon) and tumors of the ovaries and uterus.
What are the most frequent causes of Peritoneal Cancer Spread?
The cancers in which there is a high incidence of peritoneal deposits are colorectal cancer, ovarian cancer, gastric cancer, biliary tract cancers, pancreatic cancer and breast cancer.
When cancer has spread to the peritoneum is it the last stage/stage 4?
Yes spread of cancer to the peritoneum is considered stage 4 in most cancers. In ovarian cancer it is stage 3
Can stage 4 cancer be treated?
All stage 4 cancers are not the same. The outcome depends on the extent of tumor spread. Patients in whom the cancer is spread to only one organ, eg. the liver in colorectal cancer or the peritoneum in ovarian cancer do better than patients in whom more than one organ is involved
Patients with peritoneal implants (tumor deposits) often have cancer spread to the liver or lungs. In some patients however, seeding is limited to the peritoneum. It is for this subgroup of patients that surgical treatment with cytoreductive surgery and HIPEC may be possible.
With this kind of treatment, some patients can have a prolonged life and perform all the activities that people without cancer do.
In a patient with peritoneal cancer, the treatment and outcome depends on
- Primary tumor site: patients with colorectal, appendicular, ovarian cancer have a better outcome than other cancers
- Extent of metastatic spread: when multiple organs have tumor deposits, cure is usually not possible. Patients with disease limited to the peritoneum can be treated aggressively with a greater chance of cure.
- Extent of peritoneal spread: see the section on cytoreductive surgery and HIPEC
Intestinal Blockage / obstruction due to cancer
What are the Consequences of Cancer Spread to the Peritoneum?
Peritoneal cancer can lead to two main complaints:
Formation of ascites (accumulation of fluid in the abdominal cavity)
In every healthy person, a small amount of fluid is present in the abdominal cavity, to facilitate the smooth gliding of the small bowel. This fluid is being produced continuously, especially by the peritoneum of the small bowel, and is being absorbed continuously as well, especially by the peritoneum of the underside of the diaphragm and by the peritoneum of the omentum. In peritoneal cancer, there can be an imbalance between production and absorption of fluid, e.g. by blocking of the absorption by the tumor implants, resulting in ascites. The patient notices that he or she is rapidly gaining weight and that the abdomen is swelling.
Ascites caused pain, discomfort, difficulty in breathing, weakness, loss of appetite.
The tumor implants on the surface of the intestine can cause the intestine to stick to itself and to the abdominal wall, reducing mobility of the bowel and causing sharp angles. The tumor implants at the outside of the intestine can compress the intestine by their volume and block the passage of the intestinal contents. This results in abdominal cramps, vomiting, absent passage of gas and stools, and a swollen abdomen, a condition known as intestinal obstruction/malignant bowel obstruction (MBO). A solitary tumor in the large bowel (colon or rectum) could also block the lumen and cause obstruction. The treatment of this condition which is a different entity is usually surgery or stenting (refer to the section on colorectal cancer)
What is the treatment of Intestinal Blockade/obstruction?
A cancer patient can have intestinal blockage due to several reasons like previous surgery, chemotherapy or the spread of cancer itself. Bowel obstruction is sometimes due to a stool (feces) that has become hard and difficult to pass. Enemas and other measures can resolve this issue. It is important to determine the cause which may be difficult at times. The surgeon thoroughly examines and evaluates the patient and performs one or more tests like x rays, ultrasound and CT scan to study the nature of obstruction. Intestinal blockade can be complete or partial. There are 3 main types of treatments for obstruction.
- * Surgery
- * Drug therapy
- * Chemotherapy
When the blockade is complete, surgical treatment is usually required to relieve the blockade. The type of surgery will depend on the extent of the tumor and the general health of the patient to withstand the operation. Removal of the tumor: Though there may be deposits at multiple sites, only one tumor could be causing the blockade, this tumor could be removed by surgery. Bypass surgery: Some times when this is not possible, a bypass surgery is performed connecting together the intestine before and beyond the obstructing tumor. Stoma: Sometimes even this is not possible, and a loop of intestine proximal (before) to the blocked area is brought out as a stoma (opening in the intestine on the abdominal wall through which stool will collect into a bag fixed to the skin of the abdominal wall). At times when there is blockade at multiple levels, an aggressive approach is employed and the surgeon tries to remove all the tumor deposits with the goal of relieving the obstruction
Figure 3: Multiple tumor deposits out of which one is causing complete blockage. The yellow loops lie above the level of the blockage and are dilated. The orange loops are the collapsed intestine after the blockage. The area of intestine containing the tumor could be removed during surgery and the ends rejoined. Alternatively, a stoma could be created.
Figure 4: In this scenario, more than one tumor is causing blockage of the intestine. Sometimes it maybe be possible to relieve this blockage whereas in other cases, only drug therapy is feasible
Figure 5: Extensive tumor deposits on the small intestine. The small bowel is compressed and kinked in multiple areas. Surgery is usually not possible in such scenarios and only drug therapy is feasible.
Drug therapy: Drugs are used to control the symptoms like vomiting, pain abdominal distension and discomfort. Sometimes a partial blockage my get relieved with drug therapy alone. These drugs reduce the secretions of the intestine (prevent abdominal distension and vomiting), reduce the swelling in the intestines (may partially relieve the blockage) and control the pain. A tube may be inserted through the nose initially to drain the intestinal contents and prevent vomiting. Fluids are given to maintain the hydration. In experienced hands this kind of therapy enables patients to get discharged from the hospital and lead a better quality of life at home. Chemotherapy: At times certain chemotherapy drugs are also used to try and relieve the blockade. The goals of treatment of Intestinal blockage in order of priority are:
- * First, to comfort the patient and provide relief of symptoms, and enable the person to lead a good quality of life.
- * Second, to remove the blockage if possible
- * Third, to give tumor directed therapy if possible
When the blockade is partial, drug treatment is started initially and my lead to relief of the obstruction. Surgery may be undertaken if the surgeon feels the blockage can be removed or a diversion is possible and also keeping in mind the disease status and general condition of the patient.
Treatment of Peritoneal Cancer
Until recently, the classical treatment of peritoneal cancer consisted of intravenous chemotherapy. In case of obstruction, a surgical intervention, such as a bypass between the bowel segment before and the segment behind the obstruction, was often carried out. In case of ascites (peritoneal fluid), medication to expulse fluid was prescribed and punctions were performed if necessary.
What has changed recently in the Treatment of Peritoneal Cancer?
Since the last 25 years, a new form of treatment has been introduced for the management of peritoneal carcinomatosis, which consists of removal of all the gross tumor (cytoreductive surgery) followed by Hyperthermic Intraperitoneal Chemotherapy (HIPEC).
Which patients are suitable for Cytoreductive Surgery and HIPEC?
There are too main concerns: the primary site of the tumor (read the section on ‘who can be treated’) and secondly the patient condition and disease spread. For evaluating a patient’s general well being and the extent of disease spread, the surgeon performs a thorough evaluation. It is important for the patient to be in a good general condition. The blood tests and lung function should be normal. A CT scan/PET CT scan is done to evaluate the exact extent of disease in the peritoneal cavity and to rule out involvement of other organs. Patient selection is of utmost importance for the success of this treatment.
Who can be treated?
Listed below are the cancers in which peritoneal spread is treatable
Colon Cancer: In colon cancer (cancer of the large bowel), peritoneal cancer will develop in about 15% of the patients. Patients with peritoneal implants often have seeding in the liver or lungs. In 3% of all patients however, seeding is limited to the peritoneum. It is for this subgroup of patients cytoreductive surgery and HIPEC may be an option. In some selected patients with 1-3 tumors in the liver and peritoneal cancer, surgery could still be possible. Read more..
Ovarian Cancer : In ovarian cancer (cancer of the ovaries), peritoneal cancer will develop in about 75% of the patients. In patients whom the seeding is limited to the peritoneum , cytoreductive surgery is the treatement . Worldwide, HIPEC is being increasingly used to treat patients with ovarian cancer especially with stage 3 and 4 and recurrent ovarian cancer. Read more..
Pseudomyxoma Peritonei: A pseudomyxoma is a rare form of peritoneal cancer. It originates from tumors that contain a jelly like substance, mucin (mucinous tumors) , the common ones being appendicular tumors, ovarian and colorectal tumors. in the abdominal cavity. These tumor cells continue to produce jelly, which results in a swollen abdomen and sticking together of parts of the small bowel leading to intestinal obstruction. Cytoreductive surgery and HIPEC is regarded as the first choice treatment of this slowly growing tumor. Read more…
Mesotheliomas : A mesothelioma is also a rare form of peritoneal cancer which begins in the cells of the peritoneum itself. In a first, more benign, type of mesothelioma, there is much ascites (peritoneal fluid) and only small tumor implants. In a second, more malignant, type of mesothelioma, there is little ascites but larger tumor implants. Cytoreductive surgery and HIPEC can be an option, especially for the first type. Read more…
Gastric Cancer: Peritoneal seedings are frequent in stomach cancer. Stomach cancer is however much more aggressive than the cancers described above and cytoreductive surgery and HIPEC may done for selected patients with low tumor volume and good general health.
Endometrial Cancer/Cancer of the Uterus: In some endometrial cancers, there is cancer spread to the peritoneum. Cytoreductive surgery and HIPEC is beneficial for some of these patients. Read more…
Desmoplastic Small Round Cell Tumors(DSRCTs): This is a rare type of soft tissue sarcoma in the Ewings Sarcoma family of tumorsare. They are typically found in the abdomen and affect young males. Cytoreductive surgery and HIPEC has shown benefit in this cancer type. Read More..
Other Cancers: Peritoneal cancer can be caused by a lot of tumors inside or outside the abdominal cavity such as pancreas cancer, biliary cancer, sarcoma (cancer of the connective tissue) and breast cancer. At present, there are no scientific data to support the use of cytoreductive surgery and HIPEC in these settings. However, there could be some isolated cases in which circumstances favour this form of treatment and it might be used