Aim: To examine the usefulness of the histopathological finding of tumor necrosis for stratifying TNM stage IV colorectal cancer in R0 status.
Patients and methods: We enrolled 98 patients with stage IV colorectal cancer, without residual disease after resection. The extent of necrosis was assessed using published thresholds, the extent was graded as "absent", "moderate" (<30% of tumor area), or "severe" (≥30%) in each section.
Results: In multivariate analysis, the only significant difference in the disease-free survival rate was related to tumor necrosis (p=0.01) and the significant differences in the overall survival rates were related to the maximum tumor size and the degree of tumor necrosis (p=0.02 and p=0.001, respectively).
Conclusion: Tumor necrosis is associated with a poor prognosis in colorectal cancer and may allow the stratification of TNM stage IV patients without residual disease after surgery.