Peritoneal carcinomatosis in patients with digestive endocrine tumors.

Background: Peritoneal carcinomatosis (PC) in patients with digestive endocrine tumors (DET) is considered rare but its prevalence is unknown. The objectives of this study were to assess the prevalence and prognostic implications of PC in patients with various types of DET.
Methods: One hundred and sixteen consecutive patients with DET seen over a 3-year period were studied. Fifty-nine had gastrinomas, 30 had carcinoid tumors, and 27 had other types of endocrine tumors, mainly nonfunctioning ones. Diagnosis of PC was based on clinical symptoms (ascites and König's syndrome), findings of computed tomography scans that were performed at least yearly, and pathologic confirmation of tumor nodules or positive cytology in the peritoneal fluid. Factors associated with PC were investigated and the influence of PC on patients' survival was assessed.
Results: PC was found in 11 patients (overall PC prevalence: 10%; with 27% in patients with carcinoid tumors, 11% in those with nongastrinoma pancreatic endocrine tumors, and 0% in patients with gastrinomas). Nine of 11 patients with PC also had liver metastases. PC was metachronous to detection of the primary tumor in 7 of 11 patients, occurring 54 months (range, 23-273 months) after the diagnosis. In addition to the nature of the primary tumor, a greatest dimension of more than 5 cm was associated with the presence of PC in two of three patients with pancreatic endocrine tumors. In patients with carcinoid tumors, an ileal primary tumor occurred more frequently in patients with PC (87.5%) than in those without PC (50%). Prevalence of liver and other metastases was not significantly increased in patients with PC. Although five patients died of their disease, no deaths were related to PC. Actuarial survival rates at 5 years were 64% and 84% in patients with and without PC, respectively (P = not significant), whereas they were 73% and 93% in patients with and without liver metastases, respectively (P < 0.02).
Conclusions: PC is not a rare event in the course of DET, especially in patients with carcinoid tumors. It did not occur in the patient population with gastrinomas, which are less often malignant but may also differ from the other types of DET by several cell characteristics. In contrast to liver metastases, PC is not associated with a significant decrease in life expectancy.