The Risk Factors Affecting Survival in Colorectal Cancer in Taiwan

Background: Colorectal cancer (CRC) is the second and third most commonly diagnosed cancer type in females and males, respectively, representing almost 10% of the global cancer incidence. The incidence of colorectal cancer (CRC) in Taiwan is rising. Cancer survival is an indicator of the overall effectiveness of health services in the management of patients. In this study, we sought to determine the five-year survival rate of patients diagnosed with CRC and to determine factors affecting survival. Methods: In this study, we conducted a single-center, retrospective cohort study to estimate the survival outcome of patients diagnosed with colorectal carcinoma at medical center hospital in North Taiwan between 2007 and 2013. Data were extracted from medical records and the cancer database by trained data collectors. In all, 869 patients with CRC were included in this study. Survival analysis was performed using Kaplan-Meier curves, and differences between the curves were analyzed using the log-rank test. Cox proportional hazards regression models were used to analyze survival by each variable. Results: We retrospectively evaluated 869 CRC patients from 2007 to 2013. Of these, 454 subjects were males (52.24%), and the remaining (47.76%) were females. The mean and median ages at diagnosis were 63.70 years (SD = 0.45) and 64 years (range, 17-97), respectively. The mean survival time was 71.27±1.27 months. CRC-specific survival was 95.3%, 79.4% and 68.7% at 1, 3 and 5 years. The five-year survival rate for patients with stage I, II, III and IV disease was 91.20%, 82.20%, 63.20% and 21.70%. The Cox forward stepwise regression model revealed a significant potentially curable disease and risk of CRC death. The following factors were associated with a relative excess hazard for death: age ≥ 65 years (HR = 2.36, 95% CI: 1.76 - 3.17, P < 0.001); high grade of pathological differentiation (HR = 1.84, 95% CI: 1.27 - 2.66, P = 0.001); perineural nerve invasion (HR = 2.90, 95% CI: 2.03 - 4.14, P < 0.001); metastasis to distant organs (HR = 2.78, 95% CI: 2.00 - 3.87, P < 0.001); intestinal obstruction (HR = 1.38, 95% CI: 1.04 - 1.84, P = 0.026); and multiple regional lymph node metastases (HR = 1.81, 95% CI: 0.28 - 2.57, P = 0.001). Conclusion: Long-term survival from colorectal cancer remains good with 68.7% of patients being a live five years after their diagnosis. In this study, we found that perineural nerve invasion, distant metastasis, age, pathological differentiation grade, obstruction and regional lymph node metastasis are independent predictors of the survival and prognosis of patients with CRC. Perineural nerve invasion and distant metastasis appeared to be important prognostic factors affecting the entire patient cohort, and the earlier detection of CRC would improve patient survival. One limitation of this study was the small sample size; in addition, the findings were generated using data from a single medical center hospital in North Taiwan. Thus, the results of some survival comparisons were not significant. These limitations should be considered when applying these results to other districts in Taiwan that may have demographic differences. Furthermore, multicenter studies should be conducted to merge patient datasets for further research in Taiwan.