According to the results of a study presented at the 2009 annual meeting of the American Society of Clinical Oncology, breast cancer patients with small areas of cancer (“micrometastases”) in the sentinel lymph nodes should receive additional lymph node treatment (such as axillary lymph node dissection) in order to reduce the risk of cancer recurrence.
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.
The sentinel nodes are the first lymph nodes to which cancer is likely to spread. If a sentinel node biopsy determines that these nodes are free of cancer, a more extensive axillary lymph node dissection may not be required. But if the sentinel nodes are found to contain cancer, an axillary lymph node dissection is usually performed.
For some women, the sentinel node biopsy 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 sentinel 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 sentinel nodes that were free of cancer or that contained only micrometastases or isolated tumor cells. Some of the women underwent additional axillary lymph node treatment (either axillary lymph node dissection or radiation therapy to the axillary nodes), and some did not.
- Among women with sentinel node micrometastases, the five-year risk of cancer recurrence was 4.5 times higher among women who did not receive any additional axillary lymph node treatment than among women who did receive additional axillary lymph node treatment.
- Additional axillary lymph node treatment did not significantly affect recurrence rates among women with sentinel nodes that were free of cancer or that contained only isolated tumor cells.
Based on these results, the researchers recommend additional axillary lymph node treatment (either axillary lymph node dissection or radiation therapy to the axillary nodes) for women who are found to have sentinel node micrometastases. This additional treatment is important in order to reduce the risk of breast cancer recurrence.
 Tjan-Heijnen VC, Pepels MJ, de Boer M et al. Impact of omission of completion axillary lymph node dissection (cALND) or axillary radiotherapy (ax RT) in breast cancer patients with micrometastases (pN1mi) or isolated tumor cells (pN0[i+] in the sentinel lymph node (SN): Results from the MIRROR study. Presented at the 2009 annual meeting of the American Society of Clinical Oncology, May 29-June 2, 2009, Orlando, FL. Abstract CRA596.
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