Background/aims: Peritoneal washings from patients with pancreatic cancer demonstrate malignant cells in 0-58% of patients. But the significance of their potential for implantation and growth after radical surgery has not been clarified.
Methodology: Peritoneal washings were collected from 74 consecutive pancreatic cancer patients during a 5-year period and studied by conventional staining and immunocytochemical staining using anti-CEA and anti-CA 19-9. Fifty of the 74 patients were resectable and the others were nonresectable.
Results: Seven out of 8 patients with macroscopic peritoneal metastasis were positive in conventional staining, but all 8 patients were positive in immunocytochemical staining. Five of the 66 (8%) patients without macroscopic peritoneal metastasis were positive in conventional staining, but the positive rate increased to 14 of 66 (22%) in immunocytochemical staining. There was no statistically significant difference in post-operative cumulative survival rate between the 13 positive cytology patients and 37 negative cytology patients without macroscopic peritoneal metastasis.
Conclusions: The positive rate of peritoneal washings cytology was increased in this study by the use of immunocytochemical staining in addition to conventional staining. No statistically significant difference in post-operative cumulative survival rate between positive cytology patients and negative cytology patients without macroscopic peritoneal metastasis was observed.