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Introduction:Pseudomyxoma perotenei(PMP)is a rare clinical entity that mainly originates from appendiceal tumors. A subset of patients are referred after management of their primary tumor (i.e.appendectomy) for evaluation of cytoreductive surgery (CRS)and hyperthermic intraperitoneal chemoperfusion(HIPEC).Some of these patients have no visible disease on radiographic imaging and the value of further surgery in this subset remains controversial.
Mothods: Our single institution's Peritoneal Cancer Database was reviewed over a ten year period.During this time over 200 patients were treated with appendiceal cancer.We identified 44 patients who meet the criteria for none or minimal residual disease at pre-operative imaging. A CT scoring system incorporating the peritoneal carcinomatosis index (PCI) was devised where a score of zero denoted a normal scan, a score of one signified a possible minimal disease, and a score of two denotes a more obvious localized disease. This cohort of patients was reviewed for basic demographic,clinical,and pathological features. Operative treatment and postoperative course were also highlighted.
Results:Forty four patients, 15 males and 29 females, with a mean age of 50.4 years met the inclusion criteria for none or minimal disease according to the proposed CT score. The commonest initial presentation was acute appendicitis (n=22,50%), followed by nonspecific abdominal pain (n=10, 22.7%), increasing abdominal girth, and incidental diagnosis (n=5, 11.4%). Nineteen patients (43.2%) had a CT score of zero, 20 patients (45.5%) had a socre of one, and 5 patients (11.4%) a score of two. The mean PCI was 8.2 (range 0-27). A total of 22(50%) patients were upstaged when surgically explored, mostly in patients with a CT score of zero (n=6, 27.3%) and one (n=13, 59.1%). Preoperative variables including age, sex, tumor marker levels, PCI score, or presentation with a perforated appendix did not predict upstaging of disease burden. Estimated blood loss and PCI were associated with upstaging (OR= 1.007, 1.782 and p-value=0.023, 0.0007 respectively). For the entire cohort, the median survival was 22 months. Patients with CT score zero had a 25th percentile survival of 34 months, compared to those with a score of 1 (23 months), and a score of two (18 months). With a median follow-up 23 months, twenty two patients (50%) remain disease free, 11 patients (25%) are alive with disease and 8 patients have died due to disease recurrence.
Conclusion: Accurate assessment of disease burden for early stage PMP remains challenging. Our data indicates that approximately 50% of patients with no evidence of disease or minimal amount of disease can be upstaged at surgery. Based on this we recommend laparoscopic exploration and possible cytoreductive surgery and hyperthermic chemoperfusion (HIPEC) for all patients with appendiceal cancer.