Prognostic factors in survival of colorectal cancer patients after surgery.

Objective: To determine the factors affecting survival, following resection of large bowel for colorectal carcinoma.
Method: From the cancer database of a single referral institution, a total of 1090 patients who had undergone colorectal resection between 1999 and 2002 were identified. Cases with recurrent colorectal cancer or previous history of neoadjuvant chemotherapy were excluded. Survival curves were plotted using the Kaplan-Meier method. Univariate analysis of factors thought to influence survival was then made using Logrank test. Criteria studied consisted of age, sex, TNM stage, T-status, nodal status, distant metastasis, histological grade, lymphatic and vascular invasion, tumour location, preoperative carcinoembryonic antigen (CEA) level and liver function tests. Multivariate analysis was conducted using Cox regression analysis.
Results: The mean survival time for all patients was 42.8 (SEM = 2.8) months. The overall 1-, 3- and 5-year survival rates were 72%, 54% and 47%, respectively. In univariate analysis, patients' age (P < 0.0001), TNM stage (P < 0.0001), T-status (P = 0.015), nodal status (P = 0.016), distant metastasis (P < 0.0001), grade (P = 0.005), lymphatic and vascular invasion (P < 0.0001) and presurgery CEA level > 5 ng/ml (P = 0.021) were found to be predictors that could affect survival. In Cox regression analysis, age (P < 0.0001), TNM stage (P = 0.001) and grade (P = 0.008) were determined as independent prognostic factors of survival.
Conclusion: Age, TNM stage, T-status, nodal status, distant metastasis, grade, lymphatic and vascular invasion and presurgery CEA level can predict the postsurgical survival rate in patients with colorectal cancer.