Background: Pseudomyxoma peritonei (PMP) is a rare disease with an incidence rate of approximately 1 per million a year. During the past few years, there has been a survival benefit for these patients treated by complete cytoreduction and perioperative chemotherapy. Better survival rates were found in the adenomucinosis group than the carcinomatosis group. The purpose of our study was to analyze the outcome and the prognosis factors of only high-grade PMP.
Methods: We selected 38 patients from a prospective database of 59 with high-grade PMP from appendiceal origin who were treated by cytoreduction surgery and HIPEC at the Hospital University Reina Sofia (Cordoba, Spain) between 1998 and July 2012. Clinical, surgical, analytical, radiological, and histological data were obtained prospectively. Survival curves were calculated using the Kaplan-Meier method, a univariate analysis was performed and the log rank-test was used to analyze the effects of several clinical and pathologic factors on overall survival (OS) and disease-free survival (DFS).
Results: Median follow-up time was 32 months (range, 2-170). Median age at diagnosis was 57 years (range, 32-77). In 89.5 % of patients, optimal cytoreduction CC-0 (57.9 %) and CC-1 (31.6 %) was achieved. In the remaining 10.5 %, cytoreduction was classified as CC-2. The median PCI score was 21 (range, 4-38). Morbidity complications ≥ Grade 3 in the CTCAE v 3.0 classification was 18.4 %. One patient died 45 days postsurgery. Median OS at the end of follow-up was 36 months (range, 9-83); overall 5-year survival rate was 58.7 %. In the univariate analysis for OS, significant values were obtained for lymph-node involvement and suboptimal cytoreduction. The 5-year OS was 64.5 % when an optimal cytoreduction was achieved. Median DFS was 36 months (17-54); 3-year DFS rate was 49.1 %. Neoadjuvant therapy did not affect the survival of these patients; there was no difference in the 5-year OS (43 % vs. 75 %, p = 0.068).
Conclusions: In aggressive PMP, cytoreduction with peritonectomy procedure plus HIPEC is a safe procedure that suggests an improvement to the survival rates. Because optimal cytoreduction is a primary prognostic factor for survival rates, this procedure would have to be performed in an experienced center with a low morbidity. Neoadjuvant chemotherapy has not demonstrated benefits in these patients and further research will be required.