Among women with node-negative breast cancer, those who had fewer than six lymph nodes removed during axillary lymph node dissection were more likely to experience a cancer recurrence than women who had a larger number of nodes removed. These results were published in the Annals of Oncology.
Axillary lymph node dissection refers to the removal of axillary (underarm) lymph nodes in order to determine whether breast cancer has spread. Understanding the extent to which cancer has spread plays an important part in treatment planning.
Among women with node-negative cancer (cancer that has not spread to lymph nodes), some women will eventually experience a cancer recurrence. In order to better predict risk of recurrence, researchers are evaluating the relationships between tumor and treatment characteristics and patient outcomes.
In order to determine whether the number of lymph nodes removed during axillary lymph node dissection influences subsequent risk of recurrence, researchers in Spain conducted a study among 1606 women with node-negative breast cancer. All of the women had undergone axillary lymph node dissection. The number of lymph nodes removed ranged from one to 54. Half the women had more than 12 nodes removed.
Women who underwent sentinel lymph node biopsy, a newer approach to lymph node sampling, were not included in the study.
After five years, 85% of the women were alive and free of recurrence. Factors that were linked with an increased risk of recurrence as well as an increased risk of death from breast cancer were the following:
- Fewer than six lymph nodes removed during axillary lymph node dissection
- Tumor size greater than 2 centimeters
- Progesterone receptor-negative tumor
The researchers conclude that in order to be confident about a diagnosis of node-negative breast cancer, it is important to remove at least six lymph nodes during axillary lymph node dissection. The researchers note that the higher risk of recurrence among women with a small number of nodes removed may be the result of understaging (cancer that had spread to the nodes may have been missed).
It is important to note that this study did not evaluate sentinel lymph node biopsy, a newer approach to lymph node sampling.
Reference: Blancas I, Garcia-Puche JL, Bermejo B et al. Low Number of Examined Lymph Nodes in Node-negative Breast Cancer Patients is an Adverse Prognostic Factor. Annals of Oncology. Early online publication July 27, 2006.