Prognostic indicators for colorectal peritoneal metastases are different for patients with complete versus incomplete cytoreductive surgery.

Background: In the management of peritoneal metastases in patients with colorectal cancer, the completeness of cytoreduction has consistently been the most prominent prognostic indicator. Other clinical and histologic features have been described that may also have an impact on survival.

Methods: The colorectal peritoneal metastases patients treated by cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy were divided into two groups. One group had complete CRS and the second group had an incomplete CRS. The prognostic variables in these two groups of patients were statistically analyzed for their impact on survival.

Results: In the complete CRS group of 124 patients lymph node positivity, poorly differentiated histopathology, asymptomatic status following treatment with systemic chemotherapy, incomplete response to systemic chemotherapy, and moderate to high peritoneal cancer index showed a significantly reduced survival. All five of these prognostic variables ceased to show statistical significance in the group of 82 patients with incomplete cytoreduction.

Conclusion: The cause for significance of five prognostic indicators identified in patients with complete cytoreduction versus loss of significance of these indicators in patients with incomplete cytoreduction has not been determined. An absence of residual disease in complete CRS patients and a widely variable extent of residual disease in incomplete CRS patients may be important. Prognostic indicators in patients with colorectal peritoneal metastases find their greatest usefulness in patients who have had a complete cytoreduction.