Colorectal cancer is the most-common cancer of the gastrointestinal tract. The number of positive lymph nodes and total number of lymph nodes retrieved are important prognostic factors. In patients who do not receive preoperative chemoradiation, the total number of lymph nodes should be more than 12 nodes to predict accurate staging. In cases of locally-advanced rectal cancer when patients receive neoadjuvant chemoradiation it is sometimes impossible to retrieve adequate amount of lymph nodes due to the chemoradiation effect. Therefore, this study was to evaluate and predict survival rates based on positive lymph node ratio.

The primary endpoint of this study was to assess the lymph node ratio as another predictor for survival rate in preoperative chemoradiation rectal cancer patients. The other secondary objective was to determine the relationship between total harvested lymph nodes and survival rate in each stage. This is a retrospective, single-centered study, collecting data of patients from January 2011 to December 2017. Including a total of 163 patients with rectal cancer who underwent surgery following neoadjuvant chemoradiation. Using Cox regression and Kaplan-Meier survival analysis to determine whether the lymph node ratio can be used to predict the survival rate and determine the cut-off value to distinguish the prognosis of the disease.

Inclusion Criteria:

• Patients with rectal cancer who underwent surgery following neoadjuvant chemoradiation.
• Patients have tissues confirmed by Pathology
• no metastasis before surgery

Exclusion Criteria:

• Distant metastasis during surgery

Patients with rectal cancer who underwent curative surgery following neoadjuvant chemoradiation.