“Cytoreductive surgery and HIPEC/EPIC (early postoperative intraperitoneal chemotherapy) should be recommended for all patients with peritoneal dissemination of gastrointestinal malignancies, in particular, for appendiceal mucinous neoplasms,” Dr. Terence C. Chua from University of New South Wales, Sydney, Australia told Reuters Health by email. “This treatment has been shown to be effective in achieving long term disease control in the abdomen for both low grade and high grade variants of appendiceal pseudomyxoma.”
Dr. Chua and colleagues examined current results of this strategy in a retrospective study of 2298 patients treated with cytoreductive surgery for appendiceal pseudomyxoma peritonei. Their findings appear in the May 21st online Journal of Clinical Oncology.
Optimal cytoreduction was achieved in 1904 patients (83%), including complete cytoreduction in 1165 patients (51%). HIPEC was delivered intraoperatively in 2054 patients (89%).
Postoperative mortality was low (2%), but 24% of patients experienced major operative complications. Major complications were more common among patients with prior surgical score of 3, at least 2 prior operations, and peritoneal cancer index (PCI) more than 20.
Median survival was 196 months (16.3 years), and median progression-free survival was 98 months (8.2 years).
Overall survival rates were 80% at 3 years, 74% at 5 years, 63% at 10 years, and 59% at 15 years.
Prior chemotherapy treatment, peritoneal mucinous carcinomatosis histopathologic subtype, less complete debulking surgery, and major postoperative complications independently predicted poorer progression-free and overall survival. Higher peritoneal cancer index and not using HIPEC were additional predictors of poor progression-free survival, whereas older age additionally predicted poor overall survival.
“Patients with peritoneal spread of cancer should be referred to a high volume tertiary referral centre with specialized expertise in cytoreductive surgery and HIPEC/EPIC for evaluation,” Dr. Chua concluded.
“Essentially a randomized trial to confirm the results would provide level 1 evidence,” Dr. Chua explained, “but from our clinical experience and clinic interactions with patients, these retrospective and large cohort series results have made a randomized trial almost impossible to conduct due to the disparate survival outcomes, and there will likely be no patients who would commit towards such a trial especially for appendiceal pseudomyxoma.”
“Given the significant morbidity associated with cytoreductive surgery and HIPEC, one has to wonder whether an alternative approach might be prudent,” writes Dr. Eric K. Nakakura from University of California, San Francisco, in a related editorial. “There are data to suggest that similar outcomes can be obtained by the selective use of extensive debulking surgery with emphasis on preserving function and managing symptoms without routine intraperitoneal chemotherapy.”
“As with many challenging issues in oncology,” Dr. Nakakura concludes, “there remain more questions than answers with respect to the treatment of patients with pseudomyxoma peritonei.”