Prognostic Factors Influencing the Recurrence Pattern and Survival Rates in Curatively Resected Colorectal Cancer

Purpose: The treatment of colorecatal cancer depends primarily upon the stage, and whether or not the regimen of adjuvant therapy can also be decided through this staging. In fact, the clinicopathologic prognostic factors are well known. In addition to these prognostic factors, the importance of molecular biological prognostic factors has also come to light. Methods: This study was devised to analyze the recurrence pattern and the survival rate and correlate them with the prognostic factors in a group of surgically treated colorectal cancer patients, who were recruited from 1989 to 1998 at the Severance Hospital, Yonsei Uinversity College of Medicine. The survival curves were analyzed according to the Kaplan-Meier method, and the Cox regression hazard model was used to analyze the prognostic factors influencing the survival rates. Results: A total of 1973 patients were recruited, and among them 1848 (93.7%) had undergone a resection with 1643 (89.1%) having a curative resection. The overall follow-up time after surgery was 60.5±35.4 months and 1945 (98.6%) patients were confirmed to have either survived or died. The overall recurrence rate was 386/1643 (23.5%). Of these, the local recurrence rate was 86/386 (22.2%), the systemic recurrence rate was 236/386 (61.1%), and both local and systemic recurrence rates were 50/386 (12.9%). The overall 5 year survival rate was 61.5%, and according to the TNM stage, the survival rate was 84.3% for stage 1, 79.2% for stage 2, 61.5% for stage 3, and 31.5% for stage 4. Multivariate analysis indicated that the TNM stage, the number of lymph nodes involved, the gross appearance of the tumor, the positive lateral margin, vascular invasion, the preoperative CEA level (higher than 5ng/㎖), and rectal cancer were significant prognostic factors for the 5 year survival rate. Conclusions: Patient with ulceroinfiltrative, poorly differentiated, rectal cancer and the positive lateral resection margin, vascular invasion etc. had a poor survival rate after a curative resection for colorectal cancer. In addition to these clinicopathologic prognostic factors, an investigation into the molecular biological prognostic factors is also needed.ope