Metronomic Neoadjuvant Capecitabine and Cyclophosphamide in HUGE Pseudomyxoma Peritonei Patients

Inclusion Criteria: * Clinical/Histological diagnosis of pseudomyxoma peritonei (PMP); * Peritoneal Cancer Index (PCI \>28) assessed by chest and abdominal CT scan at the staging phase; * Age \>= 18 years and \<76 years; * Performance Status (ECOG \<2); * Adequate organ function including the following: * Adequate bone marrow reserve: WBC count \>3.0x109/L, absolute neutrophyl count \>1.5x109/L, platelet count \>100x109/L, and hemoglobin \>10 g/dL; * Hepatic: bilirubin \< 1.5 times the ULN, alkaline phosphatase, aspartate transaminase, and alanine transaminase \< 2.5 x UL; * Renal: Creatinine clearance \>50 mL/min or serum creatinine \<1.5 x UNL; * Patients compliance and geographic proximity that allows for adequate follow-up; * Patients must sign an informed consent document (ICD); * Male and female patients with reproductive potential must use an approved contraceptive method; Exclusion Criteria: * Peritoneal Cancer Index (PCI ≤28) assessed by chest and abdominal CT scan at the staging phase; * DPD deficiency; * Previous systemic chemotherapy and/or biological therapy; * Administration of other experimental drugs during the study Pregnancy and breast-feeding; * Serious or uncontrolled medical pathologies or active infections that would jeopardize the possibility of receiving the investigated treatment; * Disorders that could influence the absorption of capecitabine (e.g. malabsorption), intestinal occlusion, Crohn's disease or ulcerative colitis; * Psychiatric disorders, neurologic disease or other conditions that would make it impossible to comply with the protocol procedures; * Positive anamnesis with regard to other neoplastic diseases except for the ones that have been cured for more than 5 years.