2 The procedure
2.1.1 Pseudomyxoma peritonei is a rare, borderline malignant, slowly progressing tumour. It arises from the appendix or bowel and spreads throughout the peritoneal cavity, producing a large amount of mucus. Most patients will develop symptoms due to the bulk of the tumour. Most patients will eventually die of this condition, but they often survive for several years.
2.1.2 Standard treatment for pseudomyxoma peritonei is surgical debulking, in which the surgeon attempts to remove as much tumour as possible. Chemotherapy is also used. Recurrence is common, and therefore repeated debulking operations may be needed.
2.1.3 Patients with pseudomyxoma peritonei may be treated by 'watchful waiting', using surgery only when unacceptable symptoms or life-threatening complications, such as intestinal obstruction, arise.
2.2.1 The Sugarbaker technique combines complete surgical tumour removal (complete cytoreduction) with intraoperative heated chemotherapy, and is followed by postoperative intraperitoneal chemotherapy. The operation takes around 10 hours and includes:
removal of the right hemicolon, spleen, gallbladder, greater omentum and lesser omentum
stripping of the peritoneum from the pelvis and diaphragm
stripping of the tumour from the surface of the liver
removal of the uterus and ovaries in women
removal of the rectum in some cases.
2.3.1 No controlled studies were found. The studies were of poor quality. One study of 385 patients showed 5-year survival to be 86% for those with less malignant pathology (adenomucinosis) and 50% for those with more malignant pathology (mucinous adenocarcinoma). However, not all patients in this study were followed up for 5 years, and it is not clear how survival was calculated. Another study showed overall 5-year survival to be around 74% in 98 out of 321 patients who underwent repeat cytoreductive surgery. For more details, refer to the Sources of evidence section.
2.3.2 The Specialist Advisors commented that there is international controversy about the effectiveness of this procedure, given the slow natural history of pseudomyxoma peritonei. One Advisor noted that uncertainty about efficacy emanates from the difficulty in accurately diagnosing pseudomyxoma peritonei preoperatively.
2.4.1 In a study of 46 patients the main complications included: prolonged gastric paresis (almost all patients); neutropenia (49%); re-operation for postoperative complications (24%); stomach or bowel perforation (22%); enteric fistula (13%); and peripheral pressure neuropathy (11%). Most studies, however, were of poor quality with regard to safety outcomes. For more details, refer to the Sources of evidence section.
2.4.2 The Specialist Advisors listed the potential complications as: death; major blood loss; respiratory infection; peritonitis; bowel perforation; obstruction; adhesions; wound dehiscence; and wound infection. One Advisor commented that such prolonged surgery increased the risk of morbidity and mortality.