Defining stage III disease in colorectal cancer--aspects on treatment and evaluation of survival.

Background And Objective: Stage III in colorectal cancer is defined by presence of node metastasis, whereas distant growth constitutes stage IV. The aim was to describe prognosis in high risk groups of stage III in relation to survival in stage IV, along with possible effect on research and treatment.

Methods: All patients operated for stage III-IV colorectal cancer 1999-2003 (n = 591) were assessed by demography, pathology and treatment towards survival. Stage III patients were grouped by lymph node ratio (LNR) tenths and stage IV by node status (N0-2). Comparison was by cancer specific survival (CSS). Disease free survival (DFS) was also assessed for stage III.

Results: LNR predicted CSS and DFS (P < 0.001) as a higher ratio correlated with a worse prognosis and an increased risk of early recurrence. With high ratios the stage III survival prognosis resembled stage IV. A survival crossover phenomenon was found for stage III patients with a high LNR (0.9-1) compared to some stage IV patients (N0/M1).

Conclusions: The prognosis in stage III is heterogeneous and can be differentiated by LNR. The survival difference towards stage IV can be limited which could affect the use and evaluation of chemotherapy and the further development of staging terminology.