Objective: Every year, 1.8 million people are diagnosed with colon cancer. The presence of lymph node (LN) metastases is a key prognostic factor in adjuvant treatment planning and follow-up. The tumor-node-metastasis (TNM) classification can be used to assist in prognostic cancer staging. However, TNM-classification may not always compromise the necessary prognostic information. Therefore, guidelines are updated regarding prognostic value and new prognostic parameters are investigated. One of these parameters is metastatic lymph node ratio (mLNR), which is calculated by dividing the number of metastatic lymph nodes (mLNs) by the total number of lymph nodes excised. Similar publications have already reported on the prognostic value of the mLNR in gastric, pancreatic, and bladder cancer.

Methods: Pathology reports of 496 stage II and stage III patients treated for colorectal cancer (CRC) in our hospital in the last decade were retrospectively reviewed. Factors such as age, gender, tumor location, tumor size, T stage, lymphovascular invasion, perineural invasion, tumor budding, tumor deposit, total and mLN count were evaluated for overall survival.

Results: The mean tumor size was 53.8 mm. The patients who had an average of 2 LN involvement among those who had 23 lymph nodes excised were followed up for an average of 66.8 months. Receiver operating characteristic test presented the cut-off value of mLNR on overall survival was 0.028, with a sensitivity of 42% and a specificity of 71%. Gender, tumor’s localization, and size of ≥6 cm had no significant impact on survival. However, survival was related to age >60, lymphovascular, and perineural invasion, tumor deposit/budding, and mLNR >0.028 (p≤0.05). Furthermore, multivariate analysis revealed that only mLNR (p=0.034) affected overall survival independently.

Conclusion: We believe that mLNR that does not require additional costs will gain more value in diagnosis and treatment. Based on our results, mLNR may be a useful to assess prognosis in CRC patients.