Peritoneal cytology in colorectal cancer: incidence and prognostic value

BACKGROUND: The value of peritoneal washing cytology on prognosis is not clear yet. The aims of our prospective study were to consider the incidence and prognostic value of peritoneal cytology. METHODS: From 1996 to 2003, washing cytology was performed in 88 patients who underwent surgery for colorectal cancer. Before exploration and manipulation of the tumor, each of the peritoneal cavities next to the tumor site, subhepatic and rectovesical recesses, were irrigated with 50 mL saline, and then the aspirates were taken for cytological evaluation. RESULTS: Thirteen (14.7%) of 88 patients had positive cytology. Although necrosis, depth of invasion, differentiation of the tumor, macroscopic peritoneal dissemination, and ascites were correlated with positive cytology; multivariate analyses revealed the depth of invasion, presence of necrosis, and differentiation of the tumor as the factors affecting the cytology. The disease-free and overall-survival times in patients with positive and negative peritoneal washing cytology were 56.36, 61.40 and 52.08, 63.94 months, respectively (P > .05). CONCLUSION: The presence of free malignant cells in the peritoneal cavities of patients who underwent curative resection for colorectal cancer provides no further prognostic value over the current staging systems.