DIAGNOSTIC AND PROGNOSTIC VALUE OF PERITONEAL IMMUNOCYTOLOGY IN GASTRIC-CANCER

Purpose: Among the clinical factors with ct pivotal role in the predic tion of outcome for patients with gastric cancer, intraperitoneal (19) microscopic dissemination may represent an important cause of recurre nces, even in the early stages of the disease. In this context, the cy tologic examination of intraoperative peritoneal washings may be essen tial to identify metastatic free cells, although a number of false-neg ative cases may be encountered. Patients and Methods: To determine whe ther immunocytochemical (ICC) methods that used ct panel of three mono clonal antibodies (MoAbs), B72.3, AR3, and BD5, directed to gastric ca ncer-associated antigens can improve peritoneal cytology by providing more accurate prognostic indications, we immunocytochemically and morp hologically evaluated 144 peritoneal washings sampled from patients su rgically treated for gastric cancer. Results: The ICC analysis allowed the identification of metastatic free peritoneal cells in 35% of the patients, with a 14% improvement over routine cytopathology (P < .0001 ). furthermore, a 54 month survival analysis by Kaplan-Meier curves sh owed a statistically significant decrease in overall survival (OS) in patients with stages I through III disease with peritoneal microscopic disease detected morphologically and/or by ICC at the time of the pri mary surgery. Conclusion: Our data indicate that the use of a combinat ion of selected MoAbs may allow the identification of cytologically fa lse negative cases that provide valuable prognostic information. This may be useful to stratify patients on more adequate therapeutic trials . (C) 1998 by American Society of Clinical Oncology.