The following methodologies may be strictly applied to quantitatively evaluate patients with peritoneal carcinomatosis or sarcomatosis in regard to disease progression or regression: (1) Preoperative CT scan and the intraoperative assessment of cancer extent is analyzed region by region (AR-0-12) and an estimation of tumor volume (V0-V3) is evaluated according to the standardized scoring system previously described. At laparotomy, the volume of tumor nodules to adjacent organs, the viscosity (mucinous vs. solid) of tumor mass, and the pattern of distribution is assessed. (2) Radiologic abdominopelvic CT parameters that predict an incomplete cytoreduction are focal obstructions of bowel by CT assessment and tumor involvement of proximal ileum (AR-11). (3) The extent of prior surgical interventions (PS-1 through PS-3) must be recorded because aggressive deep dissections without perioperative chemotherapy severely jeopardize the possibility for complete cytoreduction. (4) Many tumor samples should be sent for histopathologic analysis. A proportion of mucin > 80% confirms a mucinous cancer. The malignant differentiation of cells, stroma morphology, the presence of signet ring cells, and evidence of invasion are used to grade cancers as mucinous tumor grade 0-3 (MTG-0 through MTG-3). (5) Once the cytoreductive procedure is accomplished, the surgeon estimates the residual volume of disease. (6) Objective response criteria from CT scan, tumor marker, and radiolabeled monoclonal antibody studies are necessary in a regular follow-up schedule.