Lymph nodes ratio is associated with the survival of colorectal cancer patients with peritoneal carcinomatosis.

The purpose of this study was to clarify the prognostic factors in patients with peritoneal carcinomatosis from colorectal origin, especially focusing on lymph node status. Between 1998 and 2007, 126 patients who underwent surgical treatment for primary colorectal cancer with peritoneal carcinomatosis were retrospectively assessed concerning prognostic factors. To estimate survival, we formulated a scoring system by numbers of independent poor prognostic factors. According to a multivariate analysis, extent of peritoneal carcinomatosis (hazard ratio, 1.93; 95% confidence interval, 1.19-3.13; P = 0.008) and lymph node ratio (hazard ratio, 1.87; 95% confidence interval, 1.05-3.33; P = 0.034) were found to be independent poor prognostic factors for survival. Furthermore, we demonstrated that score formulated by the number of these criteria was highly predictive of survival (P < 0.001). The 5-year survival rate for patients with score 0 (having no criteria), score 1 (having one criterion), and score 2 (having two criteria) were 25.1 per cent, 6.2 per cent, and 0 per cent, respectively. Lymph node ratio is an important prognostic factor in addition to the extent of peritoneal carcinomatosis after resection of primary colorectal carcinoma. Patients without these criteria have a favorable outcome, and therefore should be considered for further aggressive surgery and intraperitoneal chemotherapy.