Lymph node ratio as predictor of prognosis and treatment guide in breast cancer patients

This study evaluated whether the lymph node ratio (LNR) is an accurate predictor of breast cancer prognosis, and whether LNR can identify which patients would benefit from post-mastectomy radiation therapy (PMRT).

Breast cancer staging allows physicians to estimate prognosis, and helps guide treatment planning. Under the current staging system, patients with cancer cells detected in one to three lymph nodes are considered to be in the pN1 stage. Patients with four positive lymph nodes are considered to be in the pN2 stage. Numerous studies have shown that the number of affected lymph nodes is an indicator of increased risk, and therefore patients with pN2-stage disease are often advised to undergo post-mastectomy radiation therapy (PMRT; additional radiation therapy after removal of the breast and lymph nodes), while pN1-stage patients are offten not. This study investigated whether lymph node ratio (LNR) could provide a more accurate indication for prognosis and benefit from PMRT. LNR refers to the ratio between the number of cancer-positive lymph nodes to the total number of lymph nodes removed during surgery.

In this study, the records of 7741 breast cancer patients were examined. The LNR was calculated for each patient and, through a statistical analysis, the patients were divided into low, intermediate, and high LNR subgroups. A low LNR indicated that a small fraction of the lymph nodes that were removed in surgery were found to contain cancer cells.

3477 of the examined patients were categorized as pN1-stage patients. Among these there was a significant difference in survival between patients in the low and intermediate LNR groups. Low LNR was associated with a 76.7% 10-year survival rate, while intermediate LNR was associated with a 61.4% 10-year survival.  PMRT raised the 10-year survival rate to 81.61% in the intermediate LNR group, but did not change survival in the low LNR group.

This study concluded that lymph node ratio can be used as a predictor of cancer prognosis, and can be a useful guide when planning treatment.

This study was performed in a retrospective manner. Statistically, results of such studies have a lower confidence than of studies that examines patients currently receiving treatment in a controlled manner.

Consult with your physician regarding lymph node ratio and its implications on disease prognosis.