Clinical Study of Long-Term Survival in Colorectal Cancer Patients in Thailand: A 10-Year Follow-Up

Background: In Thailand, data on colorectal cancer (CRC) patient characteristics and overall survival (OS) rates are limited. We aimed to describe the overall 5-year, 10-year survival and to examine factors effecting the survival outcome among patients who were diagnoses of colorectal cancer.Methods: We reviewed medical records of patients diagnosed with invasive CRC from 2007 through 2016. Demographic and clinical data were collected upon diagnosis. Kaplan-Meier method and Cox proportional haz-ards model to evaluate the association of overall (OS) with risk factors.Results: A total of 3,402 CRC patients (colon 59.4%, rectum 34. 5%, and rectosigmoid 6.1%) were identified. Mean (SD) and median age were 62.9 (12.7) and 63 years old (rang 14-98 years). Stages at diagnosis were I (10.1%), II (23.3), III (35.9%) and IV (30.7%). Five-year and 10-year OS of the entire cohort were 52.7% and 41.5%, respectively. Over the part 10 years, there was a trend toward improved 5-year OS in stages I, II and III. However, 3-year OS in stage IV patients remained unchanged. Confirmed poor prognostic factors included patient age >= 65 years, high grade, and advanced stage at diagnosis.Conclusion: Advanced disease was a significant prognostic factor for shorter survival. A trend toward im-provement in 5-year OS in early stages over the past decade might be related to better surgical quality, improved radiation technique, and adjuvant chemotherapy. Given that patients received better systemic treatment in stage IV disease, the reason their OS was not improved should be examined.