Breast cancer patients with very small areas of cancer in the axillary lymph nodes (micrometastases or isolated tumor cells) appear to benefit from post-surgery treatment with chemotherapy, hormonal therapy, or both. These results were published in the New England Journal of Medicine.
Evaluation of the axillary (under the arm) lymph nodes for the presence of cancer is an important part of breast cancer staging. To assess the axillary lymph nodes, a surgeon will perform either an axillary lymph node dissection, in which many lymph nodes are surgically removed and evaluated, or a less extensive procedure known as a sentinel lymph node biopsy.
For some women, evaluation of the lymph nodes will reveal very small areas of cancer. Areas of cancer that measure between 0.2 mm and 2.0 mm are referred to as “micrometastases.” Even smaller areas of cancer are referred to as “isolated tumor cells.” The clinical significance of lymph node micrometastases and isolated tumor cells has been uncertain but was evaluated in a study conducted in the Netherlands.
The study evaluated the records of about 2,700 women who underwent surgery and sentinel lymph node biopsy for early-stage breast cancer and who had lymph nodes that were free of cancer or that contained only micrometastases or isolated tumor cells. Some of the women received systemic adjuvant therapy (hormonal therapy, chemotherapy, or both) and some did not.
- Among women who did not receive adjuvant therapy, risk of cancer recurrence or a new cancer was roughly 50% higher among women with isolated tumor cells or micrometastases than among women with cancer-free lymph nodes.
- Among women with isolated tumor cells or micrometastases, receipt of adjuvant therapy cut the risk of cancer recurrence or a new cancer by 43%.
These results suggest that women who have isolated tumor cells or micrometastases in the axillary lymph nodes have an increased risk of cancer recurrence or development of a new cancer compared with women whose lymph nodes are entirely free of cancer. Furthermore, receipt of adjuvant therapy (hormonal therapy, chemotherapy, or both) improves outcomes among women with isolated tumor cells or micrometastases.
De Boer M, van Deurzen CHM, van Dijck JAAM et al. Micrometastases or isolated tumor cells and the outcome of breast cancer. New England Journal of Medicine. 2009;361:653-63.