Treatment and Surgery options

Psudomyxoma peritonei most commonly arises from appendix tumours. Depending on the type of appendix tumour and the presentation, the following options may be considered. 

1. Watch and wait 

2. Chemotherapy 
The commonly used forms of chemotherapy (oral or intravenous) have very little role at the benign end of the spectrum. This is due to the fact that the disease is of borderline malignancy and has a very poor blood supply, so that chemotherapy does not gain access to the cells. All chemotherapy treatment relies on a balance between the benefits and risks. For a low grade tumour the risks of treatment far outweigh the benefits, and therefore the majority of oncologists (chemotherapy specialists) consider that chemotherapy has no place in the management of early pseudomyxoma peritonei. However intestinal type chemotherapy sometimes has beneficial effects if the tumour is a mucinous adenocarcinoma. (Radiotherapy does not have a place in the management of pseudomyxoma peritonei, as it is impossible to apply radiotherapy to a alarge area without causing danage to the other abdominal organs and the bowel)

3. Surgery - broadly of two types:
Major Tumour Debulking
The common surgical approach is debulking to remove as much of the tumour as possible, and generally includes removal of the uterus and ovaries in the female and often the total colon and the omentum in men and women, leaving them with a permanet bag (stoma). Disease recurrence is almost inevitable due to residual disease around the peritoneal cavity. Repeat debulking surgery may be possible, but each attempt becomes more difficult and dangerous. The small bowel becomes increasingly involved due to disease and adhesions following prior surgery and eventually surgery is impossible and is fraught with severe complications such as small bowel fistulae. 

Complete cytoreduction
Complete cytoreduction (complete removal of all visible tumour) is a technique developed and popularised by Professor Paul Sugarbaker at the Washington Cancer Centre, which is then combined with Hyperthermic Intraperitoneal Chemotherapy (HIPEC). Average operating time for what is called a ‘major peritonectomy’ is ten hours. The operation comprises a number of different procedures, namely: 

•  Right hemicolectomy 
•  Greater omentectomy 
•  Splenectomy 
•  Cholecystectomy 
•  Lesser omentectomy 
•  Pelvic peritonectomy, which sometimes includes the rectum by anterior resection and in the female includes removal of the ovaries and uterus 
•  Stripping of the peritoneum from the left hemidiaphragm 
•  Stripping of the peritoneum from the right hemidiaphragm 
•  Stripping of disease from the surface of the liver

An important factor at surgery is the involvement of the small bowel. In general the small bowel is not grossly involved due to small bowel peristalsis (normal movement of the bowel) being relatively protective against tumour implantation and growth. One of the ways of  determining involvement of the small bowel prior to surgery is a CT scan with oral contrast to outline the small bowel. 

On the CT scan sometimes it is possible to see tumour displacing the small bowel and involving it surface and  its mesentery and this is usually a poor prognostic factor. Most cases have some degree of small bowel involvement but it is usually possible to deal with limited small bowel disease. If all disease can be removed, heated Mitomycin C is given directly into the peritoneal cavity at the time of operation at a temperature of approximately 40°C. Intraperitoneal 5FU is often given for four days post-operatively.

Colorectal peritoneal metastases (peritoneal spread from colo-rectal cancer) is also treated with Cytoreduction surgery and HIPEC but the disease extent has to be fairly limited for this treatemnt to have any benefit.