Lymph node ratio as a risk factor of recurrence in stage 3 colorectal cancer

This study investigated the prognostic role of the lymph node ratio (LNR; number of lymph node metastasis per lymph nodes removed) in stage 3 colorectal cancer following post-surgery chemotherapy. Researchers suggested that LNR is strongly associated with recurrence risk (when the cancer comes back) in these patients. 

Colorectal cancer is one of the most common cancers worldwide. Although there have been rapid developments in diagnosis and treatment, a significant number of patients experience tumor recurrence and metastasis (spread to other parts of the body). Therefore, it is important to investigate ways to predict the outcomes of the cancer in order to improve the treatment plan.

Prior studies showed that the LNR is strongly associated with overall survival (time from treatment until death from any cause) in colorectal cancer. Besides the LNR, other factors are predictive of cancer outcome, such as blood levels of the proteins CEA and CA 19-9 and KRAS and BRAF mutations (permanent changes in tumor cells). However, it is not known which of these factors is more associated with colorectal cancer outcomes.

The objective of this study was to evaluate which of the prognostic factors were more associated with the risk of recurrence following post-surgery chemotherapy.

This study included information on 360 stage 3 colorectal cancer patients. Patients were treated with surgery followed by the chemotherapy 5-FU or a combined treatment of 5-FU and oxaliplatin (L-OHP). Patients were followed up at least every 3 months for the first year and every 6 months thereafter up to 5 years.

Patients with high LNR had a 96% increased risk of a worse recurrence-free survival (RFS; time from treatment to recurrence). High blood levels of CEA was associated with 3 times higher risk of recurrence, while for CA 19-9 the risk was 3.1 times higher.

Patients treated with post-surgery combined chemotherapy had better outcomes when compared with the single 5-FU therapy.

This study determined that LNR is a strong predictor of recurrence. A combination of LNR, CEA and CA 19-9 was the most accurate risk determination for colorectal cancer patients and for identification of patients who would benefit from the combined post-surgery chemotherapy with L-OHP.