Retrospective Multicenter Study of a Clinicopathologic Analysis of Pseudomyxoma Peritonei Associated with Ovarian Tumors (KGOG 3005)

Abstract

Pseudomyxoma peritonei (PMP) is a rare heterogenous disease characterized by the accumulation of massive amounts of mucinous ascites in the peritoneal cavity that arise from rupture or metastasis of a primary neoplasm of an intraperitoneal organ. Its site of origin is unclear; the most common sites are mucinous tumors of the ovary or appendix. Previous studies have investigated clinicopathologic prognostic factors of PMP, but results have been variable and controversial. This retrospective study evaluated clinicopathologic prognostic factors and determined overall survival in 35 Korean patients with PMP primarily originating from the ovary. The investigators analyzed patient medical records and follow-up data collected in the years 1995–2007. The median age of the patients was 54 years (range: 16–82). Three pathologic ovarian cell subtypes were examined: disseminated peritoneal adenomucinosis (n = 25: 71.4%), peritoneal mucinous carcinomatosis (n = 5: 14.3%), and peritoneal mucinous carcinomatosis with intermediate group (n = 5: 14.3%).The surgical stage and histologic differentiation grade was assigned to each patient. The median follow-up was 67 months. At time of diagnosis, clinical stages were IA in 2 patients (5.7%), IIIB in 4 (11.4%), IIIC in 23 (65.7%), IV in 1 (2.9%), and unknown in 5 (14.3%). The most common preoperative tumor marker was elevated CEA (84.6%); elevated CA-125 was less common (72.0%), and elevated CA-19-9 was the least common (47.4%). Thirty-four patients were treated surgically by exploratory laparotomy, cytoreduction, and appendectomy. One patient underwent radiotherapy. Twenty-seven patients received postoperative adjuvant intravenous chemotherapy and 8 received no further therapy. The overall 5-year survival rate was 87%. Univariate analysis showed that the 5-year survival rate was significantly lower in patients >50 years of age (P < .002). No other prognostic factor, neither clinical stage, histology, tumor markers nor postoperative adjuvant chemotherapy, influenced outcomes (P > .05). These data indicate that patient age is the only significant prognostic factor in PMP arising from ovarian lesions. The investigators were unable to identify independent prognostic factors of PMP originating from the ovary.