The peritoneum is a thin membrane that lines the abdominal and pelvic cavities. It covers the external surface of most of the abdominal organs. The peritoneum supports the abdominal organs and serves as a conduit for their blood, lymph vessels and nerves.
Peritoneal surface malignancy refers to a wide variety of cancers that involve the peritoneum and may also involve other abdominal organs such as spleen, large and small intestines, stomach, the liver capsule and the pelvic organs (e.g. uterus, ovaries rectum, bladder). The tumours may arise from the lining itself or may spread to the lining from other organs.
Tumours that arise from the peritoneum
Tumours that may spread to the peritoneal lining
*PMP is a unique condition characterized by diffuse collections of mucinous material in the abdomen and pelvis and mucinous implants on the peritoneal surfaces. It is generally used to refer to a group of peritoneal tumors that are frequently associated with an appendiceal tumour.
You may experience some of the following.
You might also not experience any symptoms. In certain cases, tumours are picked up when your doctor does blood tests or scans for other unrelated conditions.
Cytoreductive surgery (CRS) aims to remove all of the visible tumour in the abdomen. Intra-abdominal organs that are invaded by tumour and can be safely removed will be resected to ensure that no disease remains. Removal of the involved peritoneum will then be performed. Peritoneum that is commonly removed includes the peritoneum in the pelvis, under the diaphragm and the paracolic gutters (the right and left flanks of the abdominal cavity where the colon lies).
Once the surgical procedures are completed, hyperthermic intraperitoneal chemotherapy (HIPEC) is administered in the operating room. The chemotherapy drug is heated and maintained at a temperature of 42 degrees Celsius. HIPEC addresses the microscopic disease (tumour that is invisible to the eye) after CRS.
Heat is used to increase the effect of the chemotherapy by increasing the penetration of chemotherapy drug into the tissues and the efficacy of the chemotherapy drug in terms of toxicity.
Giving the chemotherapy during surgery has other benefits. It allows manual distribution of the drug and heat uniformly to all surfaces of the abdominal cavity. The majority of these patients will have had prior abdominal surgery to remove their primary cancers. During surgery, adhesions caused by previous surgery (scarring between peritoneal surfaces) are taken down and this ensures that the drug is uniformly distributed.
The chemotherapy is pumped in using a specialised pump that moves the heated chemotherapy solution into the abdominal cavity and then out for a constant flow. This is done over 60 minutes after which the abdominal cavity is washed and the surgery is completed.
Patients with extensive peritoneal disease that cannot be completely removed are not candidates for CRS and HIPEC. These patients may be identified pre-operatively on imaging or may only be identified during surgery. Disease on the peritoneum may be very small (millimeters) and can be difficult to detect on imaging. During surgery, if the surgeon decides that not all the tumour can be removed as the surgery may be too extensive or if too much bowel may need to be removed, the surgery may not proceed. However, debulking surgery may be an option for some patients. In these instances, we remove as much tumour as possible to lessen the symptoms.
Treatment includes cytoreductive surgery (CRS), peritonectomy and hyperthermic intraperitoneal chemotherapy (HIPEC). This involves removal of the peritoneum, any involved organ and the introduction of heated chemotherapy drug directly into the abdominal cavity. This surgical procedure aims to remove all visible tumours completely with the intention of curing. The chemotherapy treats any microscopic tumour that may be present.
Not all patients with peritoneal disease may be suitable candidates for surgery. All patients that are being considered for the surgery are discussed at our multidisciplinary tumour boards. Surgical oncologists, medical oncologists, radiation oncologists, specialized radiologists and pathologists will review the cases, any pathology and imaging. The most appropriate treatment plan for each patient is decided as a consensus.
Patients who are suitable for surgery
Upon confirmation of surgery, a date will be scheduled for surgery and you may need to go through some of the following.
The surgery may last from 4-12 hours or even longer. The duration of surgery depends on the extent of adhesions from prior surgeries, the extent of peritoneum being removed and the number of other organs requiring excision. Afterwards you will be nursed in our surgical intensive care unit (SICU) or a high-dependency unit (HDU), and discharged to the general ward when stable. The average total hospital stay is 10 days.
When you first wake up from anaesthesia, you may still have a tube in your throat to assist with your breathing. You will notice intravenous lines in place in your arms and neck. These are necessary for fluid replacement, pain medication and nutrition. A nasogastric (NG) tube inserted through your nose into the stomach for draining out the abdominal fluid. You may also have 2 to 4 abdominal catheters for drainage. During the surgery, chest tubes may be inserted, and a urinary catheter will also have been placed to assist us in monitoring your urine output.
Pain medications are usually administered via an intravenous line. It may be a continuous infusion or you may have a pump for Patient Controlled Analgesia (PCA). With a PCA, the painkillers will be given as required when you push a button for the medication.
The majority of patients stay in the SICU for one day before being transferred to the HDU. Your care will be coordinated by an intensive care physician and your surgeon.
Some patients who undergo this operation will need a temporary stoma. This will be reversed after about 2 months, on discussion with your surgeon and medical oncologist. All patients will be seen by our specialist stoma nurse before and after the operation, who will give you more information about looking after a stoma.
After your chemotherapy is completed, the chest tube is removed. The abdominal drains are removed once the output diminishes and the contents are clear. The urinary catheter will be removed at the discretion of your surgeon.
The NG tube will remain until your bowel function returns and you are able to drink. Your oral intake will be progressed from fluids to foods as decided by your surgeon.
To prevent blood clots in the leg that may travel to the lungs and cause a blockage, compression devices will be applied to your legs. This will be applied just before surgery and left on until you start walking. These may be tight and uncomfortable but are necessary to encourage blood circulation. An injection may also be given to you daily to prevent blood clots.
To prevent lung infections, your physiotherapist will work with you on deep breathing exercises. They will also supply you with a device (incentive spirometer) which you can use to continue to do the breathing exercises regularly.
Pain medication will be continued intravenously until you are able to take painkillers orally. The aim is for you to have minimal discomfort.
By the 2nd to 3rd day after surgery, we will encourage you to increase your activity. We will begin by helping you to sit out of your bed on a chair before we progress to helping you walk with assistance then independently.
As with all surgical procedures, complications can occur. Some of these risks and complications are inherent in any operative procedures, especially when general anaesthesia is administered. Complications can cause a prolonged hospitalization stay or discharge with significant home care needs. Every effort will be made to minimize the risk of having a complication; and to help you cope if a problem occurs. Your surgeon will speak to you more about these risks.
Some of the possible complications following this CRS and HIPEC are listed below. Selected complications are explained in detail below. More information will be given to you by your surgeon.
Late postoperative complications
An anastomotic leak can be a very serious complication after the operation that can lead to severe intra-abdominal infection. This may require prolonged hospitalization for intravenous antibiotics or even further surgery. In our experience, the risk of an anastomotic leak is 5%. In rare instances, a leak can present with discharge of intestinal fluid from the operative wound or skin in the form of a fistula (an abnormal passage between two organs in the body or between an organ and the exterior of the body), which will delay recovery and might even require another surgery.
This can occur in 1-3% of patients and in severe cases might require a repeat surgery to stop the bleeding.
Wound infections occur in about 5% of patients. This complication may prolong the hospital stay and delay the healing of the wound. Occasionally your wound may need to be laid open to facilitate with cleaning. Antibiotics will also be given.
Infection within the abdomen can result in abscesses and collections. If these are small, a course of antibiotics is sufficient. However, larger fluid collections will require drainage under radiological guidance or by open surgery.
Chest infection can develop after any major surgery, especially after abdominal operations, this is especially so for patients with pre-existing lung disease, and in smokers. This can prolong the hospital stay requiring intravenous antibiotics and chest physiotherapy. It is essential that you participate fully in your post-operative chest therapy to minimize the risk of a chest infection.
Bladder and sexual dysfunction
The risks of bladder and sexual dysfunction are increased when the surgery entails working within the pelvis. The problems include difficulty passing urine and impotence. The risk increases when radiation is given as part of treatment.
Such complications are rare, but include prolapse (protrude excessively), retraction into the wound and parastomal hernias. This may be managed conservatively, with surgery only becoming necessary if it causes a lot of discomfort and becomes difficult to apply the stoma bag onto the skin. Skin irritation around the stoma may result, especially when the stoma bag is not properly applied and this can be managed with topical creams.
You will be seen by your surgeon and/or medical oncologist at the outpatient unit in the National Cancer Centre Singapore at approximately 1-2 weeks after the surgery, and at least every 3 months thereafter for 1 year. Subsequently the frequency of your visits will decrease if you are well. Systemic chemotherapy will be offered by your medical oncologist if you are suitable. CT scans of your body, along with blood tests may be done at each follow-up visit. Appointments with other medical practitioners may also be arranged for you.
The major centers who perform CRS and HIPEC are mainly in the USA and Europe. To our knowledge, we have one of the largest experience in Asia. The risk of a major complication in these centers ranges from 10 to 45%, while the mortality rate ranges from 0 to 3.5%.
According to data from various centers around the world, the median 5 year survival for patients undergoing CRS and HIPEC for colorectal cancers, ovarian cancers and pseudomyxoma peritonei is 42% (20-51%), 25.4% and 87% respectively.
Since 2001, the Division of Surgical Oncology at the National Cancer Centre Singapore, has performed more than 100 CRS and HIPEC procedures for peritoneal disease from colorectal, ovarian, appendiceal, pseudomyxoma peritonei, primary peritoneal and mesothelioma patients. Our post-operative mortality rate is 2%. Our overall survival rate for 1, 3 and 5 years after CRS and HIPEC is 91.7%, 59.1% and 50.9% respectively.
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