NEW YORK (Reuters Health) – Breast cancer patients found to have micrometastases in the sentinel lymph node (SLN) but who do not undergo completion axillary lymph node dissection have low rates of regional recurrence. Therefore, in such circumstances, complete axillary lymph node dissection (ALND) and its attendant morbidity can be avoided, conclude clinicians based at Kaiser Permanente Los Angeles Medical Center in California.

“The current most common practice pattern is to perform ALND when the SLN is positive for tumor,” Dr. L. Andrew DiFronzo, and colleagues point out in the June issue of the Archives of Surgery.

However, there are many reasons to avoid completion ALND if possible, they continue. “These include the morbidity conferred by the operation; the infrequent alteration of therapy that results from the additional information obtained from knowledge of the status of non-SLN; the potential efficacy of systemic therapy and irradiation in achieving locoregional control; and the observation that a survival benefit from performing ALND has never been demonstrated.”

This prompted the researchers to examine the outcomes of 50 women who underwent breast conserving therapy for invasive cancer and had a positive SLN biopsy, but who declined completion axillary lymph node dissection.

Fourteen of these patients had nodal macrometastases (i.e., greater than 2 mm) while 33 women had micrometastases. Three patients were lost to follow-up as to outcome.

During a mean follow-up of 82 months, one of the patients with micrometastases (i.e., 3%) developed an axillary recurrence with distant metastases. The same outcome occurred in one of the patients with macrometastases (7%).

The investigators believe that these two cases involved particularly aggressive disease, and that “omitting completion ALND did not appear to have a clear impact on outcome or survival in these patients.”

Based on these findings, the authors conclude that not performing completion ALND in patients with micrometastatic disease “is reasonable and unlikely to have an adverse impact on survival and control of locoregional disease.”

Additional data are needed to see if ALND can also be avoided in patients with macrometastatic nodal involvement.

Reference:

Arch Surg 2010;145:564-569.