Sentinel node biopsy in patients with multiple breast cancer

Background: Multicentric or multifocal breast cancer is considered a limitation for sentinel lymph node biopsy (SLNB). Studies showing that all quadrants of the breast drain via common afferent lymphatic channels indicate that multiple tumors do not affect lymphatic drainage. We therefore assessed the accuracy of SLNB in patients with multiple breast tumors. Methods: Of the 942 breast cancer patients who underwent SLNB using radioisotope at Asan Medical Center between January 2003 and December 2006, 803 had unifocal and 139 had multiple tumors. Axillary dissection after SLNB was performed on 884 patients, 757 with unifocal and 127 with multiple tumors. All patients underwent lymphatic scintigram for removal of sentinel lymph nodes (SLNs). The clinical characteristics and accuracy of SLNB was compared in patients with unifocal and multiple breast cancer. Results: In the multiple tumor group, 2.68 ± 0.84 SLNs were identified in 136 of 139 patients (identification rate, 97.84%); 81.5% of SLNs were identified by scintigram. The incidence of axillary metastases was 29.50% (41/139). SLNB accuracy was 97.63% (124/127), with a false negative (FN) rate of 7.89% (3/38). In the unifocal group, 2.67 ± 0.96 SLNs were identified in 787 of 803 patients (identification rate, 98.00%); 84.8% of SLNs were identified by scintigram. The incidence of axillary metastasis was 22.04% (177/803). SLNB accuracy was 98.02% (742/757), with a FN rate of 8.62% (15/174). The accuracy and FN rate of SLNB did not differ significantly between unifocal and multiple breast cancer. Conclusion: The accuracy of SLNB in multiple breast cancer is comparable to its accuracy in unifocal cancer. These findings indicate that SLNB can be used an as alternative to complete axillary lymph node dissection in patients with multiple breast tumors.