In breast cancer patients with clinically node-negative disease, sentinel lymph node dissection (SLND) before preoperative chemotherapy is associated with accurate staging of the axilla, according to a report in the Archives of Surgery for July.
The results also indicate that although preoperative chemotherapy causes downstaging, residual nodal disease is still apparent in many patients during axillary dissection.
"The timing of SLND, before or after preoperative chemotherapy, for breast cancer is controversial," note lead author Dr. Baiba J. Grube and colleagues from Yale University School of Medicine in New Haven, Connecticut. In their study, the team investigated these approaches in 55 patients who underwent SLND before preoperative chemotherapy and in 463 control patients.
With a negative sentinel node, axillary lymph node dissection was not performed, the authors note. With a positive sentinel node, axillary dissection was performed at the time of definitive breast surgery.
One or more positive sentinel nodes were identified in 30 of the 55 patients (55%) who underwent SLND before preoperative chemotherapy, the report indicates. The sentinel node identification rate and clinical false-negative rate were 100% and 0%, respectively.
In controls with a positive sentinel node, no additional positive nodes were found in 55%, one to three nodes were seen in 25%, and four or more nodes were found in 20%. In the patients who had a positive sentinel node before preoperative chemotherapy, the corresponding percentages were 69%, 27%, and 4%.
Among patients with a positive sentinel node, a pathologic complete response in the breast was noted in 4 of 18 subjects who had a tumor-free axilla following preoperative chemotherapy, the report shows.
"The advantage of SLND before preoperative chemotherapy in clinically node-negative patients is accurate staging with high identification rates and low false-positive rates and the assurance that all nodes involved with tumor will be resected at the time of completion of axillary lymph node dissection," Dr. Grube's team concludes.
Arch Surg 2008;143:692-700.