Body surface area-based versus concentration-based intraperitoneal perioperative chemotherapy in a rat model of colorectal peritoneal surface malignancy: pharmacologic guidance towards standardization.

Worldwide, cytoreductive surgery (CRS) and hyperthermic intraperitoneal perioperative chemotherapy (HIPEC) are used in current clinical practice for colorectal peritoneal surface malignancy (PSM) treatment. Although, there is an acknowledged standardization regarding the CRS, we are still lacking a much-needed standardization amongst the various intraperitoneal (IP) chemotherapy protocols, including the HIPEC dosing regimen. We should rely on pharmacologic evidence building towards such a standardization. The current IP chemotherapy dosing regimens can be divided into body surface area (BSA)-based and concentration-based protocols. A preclinical animal study was designed to evaluate pharmacologic advantage (PA), efficacy and survival. WAG/Rij rats were IP injected with the rat colonic carcinoma cell line CC-531. Animals were randomized into three groups: CRS alone or CRS combined with oxaliplatin-based HIPEC (either BSA- or concentration-based). There was no difference in PA between the two groups (p=0.283). Platinum concentration in the tumor nodule was significantly higher in the concentration-based group (p<0.001). Median survival did not differ between the treatment groups (p<0.250). This preclinical study, in contrast to previous thinking, clearly demonstrates that the PA does not provide any information about the true efficacy of the drug and emphasizes the importance of the tumor nodule as pharmacologic endpoint.

An Unusual Location of Extraosseous Ewing's Sarcoma.

Ewing's sarcoma (ES) is the second most common malignant bone tumor in children and young adults. ES also occurs as a primary soft tissue neoplasm without involvement of bone. We report the second case of extraosseous (EO) ES emerging from the omentum and a review of the relevant literature. EO ES should be included in the differential diagnosis of soft tissue neoplasms in the abdomen.

An Unusual Case of Peritoneal Carcinomatosis.

The peritoneal surface remains an important failure site for patients with gastrointestinal and gynecologic malignancies. In the past, oncologists regarded peritoneal carcinomatosis as an incurable component of an intra-abdominal malignancy. During the last two decades, novel therapeutic approaches have emerged for peritoneal carcinomatosis patients. We report the first case of peritoneal carcinomatosis emerging from an extra-adrenal, intra-abdominal paraganglioma. This 49-year-old male was treated with cytoreductive surgery and hyperthermic intraperitoneal perioperative chemotherapy. Paragangliomas are rare tumors of neural crest-derived chromaffin cells and can originate either from the sympathetic or from the parasympathetic ganglia. It has been estimated that as many as 10% of the paragangliomas arise outside the adrenal glands. This case represents an unreported presentation of paraganglioma. Two possible origins of this malignancy, and the applied therapy, are discussed. We report the feasibility of cytoreductive surgery plus hyperthermic intraperitoneal perioperative chemotherapy in the treatment of this malignancy.