The impact of the ratio of positive nodes to removed nodes on recurrence and overall survival in node positive breast cancer patients

Purpose: The status of axillary lymph node (LN) metastasis is the most important prognostic factor in breast cancer. Postoperative regional nodal radiotherapy is recommended usually based on the number of metastatic LNs, which is associated with the total number of removed LNs during the axillary dissection. We evaluated the prognostic impact of the ratio of metastatic LNs to removed LNs on disease free survival and overall survival in breast cancer patients. Methods: The medical records of 743 breast cancer patients with metastatic axillary LNs and treated at Samsung Medical Center between 1994 and 2003 were retrospectively analyzed. The ratio of metastatic/removed LNs as well as the other prognostic factors were analyzed. Results: Both disease-free survival and overall survival rates were significantly worse in patients with a ratio of metastatic/removed LNs greater than 20% compared to those patients with a ratio of less than 20% (p=0.028, p<0.001, respectively). In patients with T1-2 and N1 breast cancer, the ratio of metastatic/removed LNs greater than 20% was significantly associated with poorer disease-free survival (p=0.027). Conclusion: A ratio of metastatic/removed LNs greater than 20% in the axilla can be an adverse prognostic factor in breast cancer patients with axillary node metastasis. In T1-2 N1 breast cancer patients, adjuvant radiotherapy as well as more aggressive chemotherapy therapy may be indicated.